Fix CSS issue on IE8

Change-Id: I1d9d32f056e026e290b6161dd99e3c2bd7d53318
Merge commit 'refs/changes/19/2319/1' of http://gerrit.tuleap.net/tuleap into HEAD

* http://gerrit.tuleap.net/tuleap:
  Fix CSS issue on IE8

Change-Id: I1cedd9757b1ef067052b3fb657e81bcd036e3938
This is Tuleap 6.12.99.63

Change-Id: I6a46f638fa4bcdb9552fc6015611f2b98c9bb91f