request #5857 - SYSTEM_CHECK : Error with SVN

Do not throw an exception when hook is linked to hook

Change-Id: If3c60ccb7bdb6ccfe8ac8cb809c267dd7acd3589
Merge commit 'refs/changes/15/1915/1' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  request #5857 - SYSTEM_CHECK : Error with SVN

Change-Id: I08a6017e120e0743224546f88268fa6cb21486a4
This is Tuleap 6.10.99.26

Change-Id: I7aa4f4fc1f65cb69e533a35b7dd36edfca5e8b25