Core/Backend - only parse stream results when configd socket could be…

… opened. closes #7142

Although this isn't the reason why configd wasn't running, it should not crash either when already sending messages to syslog about the startup issue.

src/opnsense/mvc/app/library/OPNsense/Core/Backend.php

@@ -147,7 +147,7 @@ public function configdRun($event, $detach = false, $timeout = 120, $connect_tim
 
         // read response data
         $starttime = time();
-        while (true) {
+        while (is_resource($stream)) {
             $resp = $resp . stream_get_contents($stream);
 
             if (strpos($resp, $endOfStream) !== false) {