Fix bridges potentially not connecting on Windows.

Closes #478.

ChangeLog.txt

@@ -3,6 +3,7 @@ Broker:
   protocol error. Closes #1367.
 - Fix support for libwebsockets 3.x.
 - Fix slow websockets performance when sending large messages. Closes #1390.
+- Fix bridges potentially not connecting on Windows. Closes #478.
 
 Documentation:
 - Improve details on global/per listener options in the mosquitto.conf man page.

lib/packet_mosq.c

@@ -239,7 +239,11 @@ int packet__write(struct mosquitto *mosq)
 #ifdef WIN32
 				errno = WSAGetLastError();
 #endif
-				if(errno == EAGAIN || errno == COMPAT_EWOULDBLOCK){
+				if(errno == EAGAIN || errno == COMPAT_EWOULDBLOCK
+#ifdef WIN32
+						|| errno == WSAENOTCONN
+#endif
+						){
 					pthread_mutex_unlock(&mosq->current_out_packet_mutex);
 					return MOSQ_ERR_SUCCESS;
 				}else{