Merge pull request #6888 from yang-g/fixes

Minor fixes

src/core/lib/iomgr/udp_server.c

@@ -243,13 +243,13 @@ static int prepare_socket(int fd, const struct sockaddr *addr,
 
   if (!grpc_set_socket_sndbuf(fd, buffer_size_bytes)) {
     gpr_log(GPR_ERROR, "Failed to set send buffer size to %d bytes",
-            buf_size_bytes);
+            buffer_size_bytes);
     goto error;
   }
 
   if (!grpc_set_socket_rcvbuf(fd, buffer_size_bytes)) {
     gpr_log(GPR_ERROR, "Failed to set receive buffer size to %d bytes",
-            buf_size_bytes);
+            buffer_size_bytes);
     goto error;
   }