if thumbnail error thrown, handle as warning not Error

Author: n8fr8

src/org/ffmpeg/android/MediaUtils.java

@@ -12,10 +12,10 @@ public static Bitmap getVideoFrame(String videoPath,long frameTime) {
             retriever.setDataSource(videoPath);                   
             return retriever.getFrameAtTime(frameTime, MediaMetadataRetriever.OPTION_CLOSEST);
         } catch (IllegalArgumentException ex) {
-            Log.e("MediaUtils", "error getting video frame", ex);
+            Log.w("FFMPEG.MediaUtils", "illegal argument exception");
 
         } catch (RuntimeException ex) {
-        	Log.e("MediaUtils", "error getting video frame", ex);
+        	Log.w("FFMPEG.MediaUtils", "error getting video frame");
                                 } finally {
             try {
                 retriever.release();