remove redundant mMusicFader variable

apps/openmw/mwsound/soundmanagerimp.cpp

@@ -336,10 +336,9 @@ namespace MWSound
             return;
         }
 
-        mMusicFader = 0.5f;
         mNextMusic = filename;
 
-        mMusic->setFadeout(mMusicFader);
+        mMusic->setFadeout(0.5f);
     }
 
     void SoundManager::streamMusic(const std::string& filename)

apps/openmw/mwsound/soundmanagerimp.hpp

@@ -121,7 +121,6 @@ namespace MWSound
         void updateWaterSound(float duration);
         void updateMusic(float duration);
 
-        float mMusicFader;
         std::string mNextMusic;
 
         float volumeFromType(PlayType type) const;