Fix music playing when crepitus is present (#341)

UseCreatureMusic( HostileZombiesPresent() ); was overriding the music mode set in PrepareCreaturesForBattle() when encountering crepitus or being in the creature caves, resulting in regular tense and battle music being played.

Tactical/Merc Entering.cpp

@@ -991,7 +991,7 @@ void HandleFirstHeliDropOfGame( )
 			SayQuoteFromAnyBodyInSector( QUOTE_ENEMY_PRESENCE );
 			
 			// Start music
-			UseCreatureMusic(HostileZombiesPresent());
+			CheckForZombieMusic();
 
 #ifdef NEWMUSIC
 			GlobalSoundID  = MusicSoundValues[ SECTOR( gWorldSectorX, gWorldSectorY ) ].SoundTacticalTensor[gbWorldSectorZ];