Make groups management compatible with Django 1.10+
Make groups management compatible with Django 1.10+


Former-commit-id: f996da44520a1c4e1c395c5e7e8a4476be5093dc [formerly 8ca04e4792e891bac69e8c0ac9731095bf61f768]
Former-commit-id: 1d6ad5654a3457be8b878d7c4798c14692a809a7
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine