initialize this just to prevent loose ends

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9912 387891d4-d844-0410-90c0-e4c51a9137d3
fix Mantis #2931: don't prematurely exit the model_interp_tmappoly method if we're drawing outlines

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9913 387891d4-d844-0410-90c0-e4c51a9137d3