Make sure onExit is called if there is no audio stream

Author: eschmar

gpuv/src/main/java/com/daasuu/gpuv/camerarecorder/GPUCameraRecorder.java

@@ -230,7 +230,7 @@ public void onExit(final MediaEncoder encoder) {
             if (encoder instanceof MediaAudioEncoder && audioStopped) {
                 audioExitReady = true;
             }
-            if (videoExitReady && audioExitReady) {
+            if (videoExitReady && (audioExitReady || mute)) {
                 cameraRecordListener.onVideoFileReady();
             }
         }