util/qemu-sockets: fix keep_alive handling in inet_connect_saddr

In "if (saddr->keep_alive) {" we may already be on error path, with
invalid sock < 0. Fix it by returning error earlier.

Reported-by: Coverity (CID 1405300)
Fixes: aec21d31756cbd
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20190910075943.12977-1-vsementsov@virtuozzo.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

util/qemu-sockets.c

@@ -461,12 +461,13 @@ int inet_connect_saddr(InetSocketAddress *saddr, Error **errp)
         }
     }
 
+    freeaddrinfo(res);
+
     if (sock < 0) {
         error_propagate(errp, local_err);
+        return sock;
     }
 
-    freeaddrinfo(res);
-
     if (saddr->keep_alive) {
         int val = 1;
         int ret = qemu_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,