make group_id be id (after the opposite was done)

api/v3/Group.php

@@ -108,6 +108,9 @@ function civicrm_api3_group_get($params) {
     $returnProperties['id'] = 1;
     $returnProperties = array_keys($returnProperties);
   }
+  if (CRM_Utils_Array::value('group_id', $inputParams)) {
+    $inputParams['id'] = $inputParams['group_id'];
+  }
   $groupObjects = CRM_Contact_BAO_Group::getGroups($inputParams, $returnProperties, $sort, $offset, $rowCount);
   if (empty($groupObjects)) {
     return civicrm_api3_create_success(FALSE);