Audio|Client: Try other music sources if playback fails

Although the preferred source may be available playback may still
fail for some reason (e.g., the preferred source is CD audio yet
the specified track number does not exist).

If playback does fail, then continue to try all sources according
to the user's preferred order.

doomsday/client/src/audio/s_mus.cpp

@@ -362,7 +362,8 @@ int Mus_Start(Record const *rec, bool looped)
         case MUSP_CD:
             if(Mus_GetCD(rec))
             {
-                return AudioDriver_Music_PlayCDTrack(Mus_GetCD(rec), looped);
+                if(AudioDriver_Music_PlayCDTrack(Mus_GetCD(rec), looped))
+                    return true;
             }
             break;
 
@@ -374,7 +375,8 @@ int Mus_Start(Record const *rec, bool looped)
                         << rec->gets("id") << NativePath(Str_Text(&path)).pretty();
 
                 // Its an external file.
-                return AudioDriver_Music_PlayFile(Str_Text(&path), looped);
+                if(AudioDriver_Music_PlayFile(Str_Text(&path), looped))
+                    return true;
             }
 
             // Next, try non-MUS lumps.
@@ -385,18 +387,13 @@ int Mus_Start(Record const *rec, bool looped)
         case MUSP_MUS:
             if(AudioDriver_Music_Available())
             {
-                String const lumpName = rec->gets("lumpName");
-                lumpnum_t lumpNum = App_FileSystem().lumpNumForName(lumpName);
-                if(lumpNum >= 0)
-                {
-                    int result = Mus_StartLump(lumpNum, looped, canPlayMUS);
-                    if(result < 0) break;
-                    return result;
-                }
+                lumpnum_t const lumpNum = App_FileSystem().lumpNumForName(rec->gets("lumpName"));
+                if(Mus_StartLump(lumpNum, looped, canPlayMUS) == 1)
+                    return true;
             }
             break;
 
-        default: DENG_ASSERT(!"Mus_Start: Invalid value for order[i]"); break;
+        default: DENG2_ASSERT(!"Mus_Start: Invalid value for order[i]"); break;
         }
     }