TSG-7767: 修复内存泄漏，对返回值判断不严谨，返回0xFFFFFFFF到SAPP，导致CLOSE状态未释放内存

src/gquic_process.cpp

@@ -849,7 +849,7 @@ int gquic_frame_type_stream(struct streaminfo *pstream, struct _quic_context* _c
 //frame type->stream->offset->data length
 int gquic_proc_unencrypt(struct streaminfo *pstream, struct _quic_context* _context, void *a_packet, char * payload, int payload_len, int *used_len)
 {
-	unsigned int ret=0;
+	int ret=0;
 	unsigned char frame_type=0;
 	unsigned int stream_id=0;
 	unsigned int error_code=0;