Fixed regex in hostname validator

src/psm/Util/Server/ServerValidator.php

@@ -96,7 +96,7 @@ class ServerValidator {
 			case 'ping':
 				if (!filter_var($value, FILTER_VALIDATE_IP)
 					// domain regex as per http://stackoverflow.com/questions/106179/regular-expression-to-match-hostname-or-ip-address :
-					&& !preg_match("/^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])/", $value)
+					&& !preg_match("/^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])$/", $value)
 				) {throw new \InvalidArgumentException('server_ip_bad_service'); }
 				break;
 		}