remote: Don't print a warning every time a remote call fails

$ sudo virsh pool-start idontexist
10:58:18.716: warning : processCallDispatchReply:7612 : Method call error
error: failed to get pool 'idontexist'
error: Storage pool not found: no pool with matching name 'idontexist'

That warning doesn't server much purpose being printed via a virsh call. So
remove the message.

src/remote/remote_driver.c

@@ -7606,7 +7606,6 @@ processCallDispatchReply(virConnectPtr conn, struct private_data *priv,
         return 0;
 
     case REMOTE_ERROR:
-        VIR_WARN0("Method call error");
         memset (&thecall->err, 0, sizeof thecall->err);
         if (!xdr_remote_error (xdr, &thecall->err)) {
             error (in_open ? NULL : conn,