using NSMutableArray sortUsingFunction instead of NSArray sortedArrayUsingFunction

性能优化，同时也会修正多线程下使用LFStreamSocket推流的内存泄漏问题

Author: linyehui

LFLiveKit/publish/LFStreamingBuffer.m

@@ -62,9 +62,7 @@ - (void)appendObject:(LFFrame *)frame {
     } else {
         ///< 排序
         [self.sortList addObject:frame];
-        NSArray *sortedSendQuery = [self.sortList sortedArrayUsingFunction:frameDataCompare context:NULL];
-        [self.sortList removeAllObjects];
-        [self.sortList addObjectsFromArray:sortedSendQuery];
+		[self.sortList sortUsingFunction:frameDataCompare context:nil];
         /// 丢帧
         [self removeExpireFrame];
         /// 添加至缓冲区