request #7474 - Error 500 when updating an artifact without status

Change-Id: Ia684c8a8930bf2c78b213378fcb704d7f37ea98e
Merge commit 'refs/changes/51/3051/9' of ssh://gerrit.tuleap.net:29418/tuleap into tuleap-stable-master

* ssh://gerrit.tuleap.net:29418/tuleap:
  request #7474 - Error 500 when updating an artifact without status

Conflicts:
	plugins/tracker/include/autoload.php

Change-Id: Ic865d857a118dfd052b45d3374865059931ab0a1
Tuleap 7.5.99.48

Change-Id: I6dea2ac5b5d267119f6957e860eaa7e83904d1f3