Uninstall doesn't remove all module-related variables

I'll return to this with more details when I have time to investigate. But I'll create the issue for now so that it's up here and ready for me or someone else to return to.

I have a site that uses service_links, and I moved the directory in which the module was installed. That's something that you can normally do - clear all caches, the registry finds the new module location, and everything works.

Not in this case - the module was still trying to load the icons from the old file location. So I disabled and uninstalled the module, and then re-enabled it. It was still looking in the old location. I searched the database, and found that
the icon locations are stored in a variable named service_links_path_icons.

Uninstalling the module should have removed that variable. I uninstalled a second time, and checked to confirm: The variable was still in the database after the uninstall. This time, I manually removed the variable before re-enabling the module, and everything works fine.

But that flagged up that the module does not remove the service_links_path_icons variable from the database on uninstall. I'd need to have a bigger dig to find out if other variables are also getting left behind, and a longer dig to come up with a patch.