only warn once, because old missions tended to have a *lot* of these broken +Team values

git-svn-id: svn://svn.icculus.org/fs2open@10404 387891d4-d844-0410-90c0-e4c51a9137d3
wing names with the hash at the beginning aren't subject to the name bashing

git-svn-id: svn://svn.icculus.org/fs2open@10405 387891d4-d844-0410-90c0-e4c51a9137d3