remove dead code for project-issue vs. project_issue menu items

when i was first porting this to 5.x, i thought the node/add/project-issue (hyphen) vs. node/add/project_issue (underscore) problem was going to cause major link rot. so, i added a menu item and a drupal_goto() to try to provide support for the legacy location. however, i've since discovered that core handles this automatically. so, not only is this dead code, it also doesn't handle all the URL args properly, so, for example, if you use OG and create an issue associated with a group, that gets clobbered by the drupal_goto() i added.