io: fix copy+paste mistake in socket error message

s/write/read/ in the error message reported after
readmsg() fails

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

io/channel-socket.c

@@ -569,7 +569,7 @@ static ssize_t qio_channel_socket_readv(QIOChannel *ioc,
                 goto retry;
             } else {
                 error_setg_errno(errp, socket_error(),
-                                 "Unable to write to socket");
+                                 "Unable to read from socket");
                 return -1;
             }
         }