fix nothing draggable bug on cardwall renderer

Change-Id: I257e75d3705558d499ddb67968382a4e8b72235f
Merge commit 'refs/changes/67/567/4' of ssh://gerrit.tuleap.net:29418/tuleap into tuleap-stable-master

* ssh://gerrit.tuleap.net:29418/tuleap:
  fix nothing draggable bug on cardwall renderer

Change-Id: I63e2e6f91aef694cddee31622bd0fb017a1cc803
Tuleap 6.1.99.36

Change-Id: I05aef4ab440d261a3feafed30cef44730d9d2fd4