the game doesn't like it when you do an Assertion while it's shutting down

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9996 387891d4-d844-0410-90c0-e4c51a9137d3
and that shouldn't have been committed in r9995

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9997 387891d4-d844-0410-90c0-e4c51a9137d3