tasks #6679: hide references sidebar on IE7

+ fix IE7 javascript issue

Change-Id: I694b566ec55b3de7825146b071ba5d5b3b7e4ad8
Merge commit 'refs/changes/32/2332/4' of ssh://gerrit.tuleap.net:29418/tuleap into HEAD

* ssh://gerrit.tuleap.net:29418/tuleap:
  tasks #6679: hide references sidebar on IE7

Change-Id: I70165085a8b017e9299936118e6cc28ece596b92
This is Tuleap 6.12.99.76

Change-Id: If5c7923b41b3a8573040604469e2fcec076e6f7e