fix tasks #7142: system event error on new version of document (not introduced in this story)

Change-Id: Ic8c6407d4a772a0ae685aaabc7a9cfc804add53a
Merge commit 'refs/changes/10/2710/3' of ssh://gerrit.tuleap.net:29418/tuleap into tuleap-stable-master

* ssh://gerrit.tuleap.net:29418/tuleap:
  fix tasks #7142: system event error on new version of document (not introduced in this story)

Change-Id: I5a3c80b15b539dd381b3ddcf23cf21f660f0628f
Tuleap 7.2.99.16

Change-Id: Ia6d5641942c98bf8701edeee6111d9dc233c1934