Fix request #7057 Fatal error when searching in wiki

Change-Id: Ibc7a3865653597f9db4da16f238fe6b9b1e87daa
Merge commit 'refs/changes/45/2645/1' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  Fix request #7057 Fatal error when searching in wiki

Change-Id: I7e9cca1d9e507d79e8306e8751dfcd5667e63309
This is Tuleap 7.1.99.39

Change-Id: I1f716e8f94a22e23112ea6a277e808f69385118c