tasks #6828 - Launch system event for migration

Change-Id: Ie2b88c6aeef77658bac9e11c8664e9e5bd62da5e
Merge commit 'refs/changes/35/2435/6' of http://gerrit.tuleap.net/tuleap into HEAD

* http://gerrit.tuleap.net/tuleap:
  tasks #6828 - Launch system event for migration

Change-Id: Ieeb708a49de23f6ea46a70c7dcc5930f80ab54f4
This is Tuleap 7.0.99.34

Change-Id: I4a8bf7af208dbd96cf9decdea0d4758400e16848