webui: Fix infinite loop when trying to log in with invalid account

Close socket on fwrite() error. fwrite() returns the number of bytes
written, or false on error.

Fixes #1324: Infinite loop when trying to log with invalid account

(cherry picked from commit 2f58278)

webui/vendor/Bareos/library/Bareos/BSock/BareosBSock.php

@@ -217,7 +217,7 @@ private function send($msg)
       $str_length += 4;
       while($this->socket && $str_length > 0) {
          $send = fwrite($this->socket, $msg, $str_length);
-         if($send === 0) {
+         if($send === 0 || $send === false) {
             fclose($this->socket);
             $this->socket = null;
             return false;