fix crash (cocos2d#18375)

Author: minggo

cocos/audio/ios/CDAudioManager.m

@@ -417,7 +417,7 @@ - (id) init: (tAudioManagerMode) mode {
     if ((self = [super init])) {
 
          [[NSNotificationCenter defaultCenter] addObserver: self
-         selector:    NSSelectorFromString(@"handleInterruption")
+         selector:    NSSelectorFromString(@"handleInterruption:")
          name:        AVAudioSessionInterruptionNotification
          object:      [AVAudioSession sharedInstance]];