MDEV-9749 InnoDB receives 'Bad file descriptor' error, possibly related to feedback plugin

and
MDEV-10250 InnoDB: Error: File (unknown): 'close' returned OS error 209. Cannot continue operation"

after a failed connect() feedback plugin was continuing with the
file descriptor, trying to send the data (which failed) and
closing it at the end. Even though this fd might've been reused for
something else already.

plugin/feedback/url_http.cc

@@ -190,6 +190,7 @@ int Url_http::send(const char* data, size_t data_length)
       break;
 
     closesocket(fd);
+    fd= INVALID_SOCKET;
   }
 
   freeaddrinfo(addrs);