Cannot enable sharemessage_demo properly

Problem/Motivation

After pulling the branch, I've tried to install sharemessage_demo in two different machines/systems, still got an error, and the module is not enabled, but if you do it manually through the UI everything looks fine except for the demo content that is not installed. Pasted the error message trying to enable the demo module via drush

Clean branch:

exception 'Drupal\Core\Config\PreExistingConfigException' with message 'Configuration objects (core.entity_form_display.node.sharecontent.default, core.entity_view_display.node.sharecontent.default,                             [error]
field.field.node.sharecontent.body, node.type.sharecontent, sharemessage.sharemessage.share_message_addthis_demo) provided by sharemessage_demo already exist in active configuration' in
/usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Config/PreExistingConfigException.php:65
Stack trace:
#0 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Config/ConfigInstaller.php(471): Drupal\Core\Config\PreExistingConfigException::create('sharemessage_de...', Array)
#1 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/ProxyClass/Config/ConfigInstaller.php(132): Drupal\Core\Config\ConfigInstaller->checkConfigurationToInstall('module', 'sharemessage_de...')
#2 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Extension/ModuleInstaller.php(141): Drupal\Core\ProxyClass\Config\ConfigInstaller->checkConfigurationToInstall('module', 'sharemessage_de...')
#3 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/ProxyClass/Extension/ModuleInstaller.php(83): Drupal\Core\Extension\ModuleInstaller->install(Array, true)
#4 /usr/local/source/drush/commands/core/drupal/environment.inc(131): Drupal\Core\ProxyClass\Extension\ModuleInstaller->install(Array, true)
#5 /usr/local/source/drush/commands/core/drupal/environment.inc(198): drush_module_install(Array)
#6 /usr/local/source/drush/commands/pm/pm.drush.inc(1167): drush_module_enable(Array)
#7 [internal function]: drush_pm_enable('sharemessage_de...')
#8 /usr/local/source/drush/includes/command.inc(366): call_user_func_array('drush_pm_enable', Array)
#9 /usr/local/source/drush/includes/command.inc(217): _drush_invoke_hooks(Array, Array)
#10 [internal function]: drush_command('sharemessage_de...')
#11 /usr/local/source/drush/includes/command.inc(185): call_user_func_array('drush_command', Array)
#12 /usr/local/source/drush/lib/Drush/Boot/BaseBoot.php(67): drush_dispatch(Array)
#13 /usr/local/source/drush/includes/preflight.inc(66): Drush\Boot\BaseBoot->bootstrap_and_dispatch()
#14 /usr/local/source/drush/drush.php(12): drush_main()
#15 {main}

Branch with a patch applied (not sure if this is a useful info...):

exception 'Symfony\Component\Routing\Exception\RouteNotFoundException' with message 'Route "sharemessage.settings.settings" does not exist.' in /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Routing/RouteProvider.php:187   [error]
Stack trace:
#0 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Routing/UrlGenerator.php(425): Drupal\Core\Routing\RouteProvider->getRouteByName('sharemessage.se...')
#1 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Routing/UrlGenerator.php(277): Drupal\Core\Routing\UrlGenerator->getRoute('sharemessage.se...')
#2 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Render/MetadataBubblingUrlGenerator.php(105): Drupal\Core\Routing\UrlGenerator->generateFromRoute('sharemessage.se...', Array, Array, true)
#3 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Url.php(735): Drupal\Core\Render\MetadataBubblingUrlGenerator->generateFromRoute('sharemessage.se...', Array, Array, false)
#4 /usr/local/var/www/d8.dev/www/modules/sharemessage/modules/sharemessage_demo/sharemessage_demo.install(26): Drupal\Core\Url->toString()
#5 [internal function]: sharemessage_demo_install()
#6 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Extension/ModuleHandler.php(391): call_user_func_array('sharemessage_de...', Array)
#7 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/Extension/ModuleInstaller.php(287): Drupal\Core\Extension\ModuleHandler->invoke('sharemessage_de...', 'install')
#8 /usr/local/var/www/d8.dev/www/core/lib/Drupal/Core/ProxyClass/Extension/ModuleInstaller.php(83): Drupal\Core\Extension\ModuleInstaller->install(Array, true)
#9 /usr/local/source/drush/commands/core/drupal/environment.inc(131): Drupal\Core\ProxyClass\Extension\ModuleInstaller->install(Array, true)
#10 /usr/local/source/drush/commands/core/drupal/environment.inc(198): drush_module_install(Array)
#11 /usr/local/source/drush/commands/pm/pm.drush.inc(1167): drush_module_enable(Array)
#12 [internal function]: drush_pm_enable('sharemessage_de...')
#13 /usr/local/source/drush/includes/command.inc(366): call_user_func_array('drush_pm_enable', Array)
#14 /usr/local/source/drush/includes/command.inc(217): _drush_invoke_hooks(Array, Array)
#15 [internal function]: drush_command('sharemessage_de...')
#16 /usr/local/source/drush/includes/command.inc(185): call_user_func_array('drush_command', Array)
#17 /usr/local/source/drush/lib/Drush/Boot/BaseBoot.php(67): drush_dispatch(Array)
#18 /usr/local/source/drush/includes/preflight.inc(66): Drush\Boot\BaseBoot->bootstrap_and_dispatch()
#19 /usr/local/source/drush/drush.php(12): drush_main()
#20 {main}

Don't know why the fix from #2718759: Follow up for Share Message Demo cleanups is not working...

Proposed resolution

- find the bug
- upload the patch

Remaining tasks

User interface changes

API changes

Data model changes