Fix for edge case where an inactive User shadows the primary username.

When the selected primary user tries to save itself with the primary username, a database error results. The simplest solution is to delete the inactive user, if it should exist. It should be safe to delete an inactive user, as the user was either never activated originally, or was deactivated as a result of a merge.
Merge pull request #2 from Crossway/bug/inactive-shadow-username

Fix for edge case where an inactive User shadows the primary username.