WebSession: fix group management pages
WebSession: fix group management pages

* Amends callers of webmessage's perform_request_send() that had changed
  APIs.  This fixes some tracebacks on the group management pages.

tiborsimko/invenio-accounts,tiborsimko/invenio-accounts,inspirehep/invenio-accounts,inveniosoftware/invenio-accounts,tiborsimko/invenio-accounts,inveniosoftware/invenio-accounts,inspirehep/invenio-accounts,inspirehep/invenio-accounts,inveniosoftware/invenio-accounts