TT#149462 Form/Administrator/Reseller role_id required=0

* role_id field is set to optional as the API uses the
  form and there is no support for the role_id there yet

Change-Id: Ib663b4d9d0501eca2310a7e95733c2166c9872eb

lib/NGCP/Panel/Form/Administrator/Reseller.pm

@@ -36,7 +36,7 @@ sub field_list {
             options => [
                 $self->_acl_role_select_options()
             ],
-            required => 1,
+            required => 0,
             element_attr => {
                 rel => ['tooltip'],
                 title => ['Role']