Issue nostra13#602: Prevent IOException suppressing at the end of file copying

Author: nostra13

library/src/com/nostra13/universalimageloader/utils/IoUtils.java

@@ -74,6 +74,7 @@ public static boolean copyStream(InputStream is, OutputStream os, CopyListener l
 			current += count;
 			if (shouldStopLoading(listener, current, total)) return false;
 		}
+		os.flush();
 		return true;
 	}