[463000] Fix reconnect bug on Windows.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=463000

ChangeLog.txt

@@ -6,6 +6,7 @@ Broker:
 
 Client library:
 - Inflight limits should only apply to outgoing messages. Closes #461620.
+- Fix reconnect bug on Windows. Closes #463000.
 
 
 1.4 - 20150218

lib/mosquitto.c

@@ -931,7 +931,7 @@ int mosquitto_loop(struct mosquitto *mosq, int timeout, int max_packets)
 					}
 				}
 			}
-			if(mosq->sockpairR >= 0 && FD_ISSET(mosq->sockpairR, &readfds)){
+			if(mosq->sockpairR != INVALID_SOCKET && FD_ISSET(mosq->sockpairR, &readfds)){
 #ifndef WIN32
 				if(read(mosq->sockpairR, &pairbuf, 1) == 0){
 				}