Do not display a cardwall on AD front page when there is nothing to show

So tuleap.net doesn't seem to be broken for non Tuleap expert user

Change-Id: I28261e7c6020d88b14e91b48aab697c7a494118c
Merge commit 'refs/changes/42/642/2' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  Do not display a cardwall on AD front page when there is nothing to show

Change-Id: I84586d08703024748e4ccec59e961adc60ae6eb1
This is Tuleap 6.2.99.24

Change-Id: I9342f3af3555297d9913ccc402a6606676e0f2fb