added exception on wrong ogc:Filter in wfs api

SE/se-lib/Api/WfsDataServer.php

@@ -59,6 +59,7 @@ class Api_WfsDataServer extends Api_WfsServerBase {
 			$reqBody = Request::getRequestBody();
 			if (!empty($reqBody)) {
 				$ogcFilter = $this->convertOgcFilterFromRequestBody($reqBody);
+				if (empty($ogcFilter)) throw new Api_WfsException("Error Processing ogc:Filter", 501);
 			}
 		}
 		if ('hits' == V::get('resultType', '', $_REQUEST)) {// resultType=hits