Fix libnss-mysql db name

Change-Id: Id2c057a45b7fc8e0c22fb8a0036b768d440596ac
Merge commit 'refs/changes/20/420/2' of http://gerrit.tuleap.net/tuleap into tuleap-stable-master

* http://gerrit.tuleap.net/tuleap:
  Fix libnss-mysql db name
Tuleap 5.12.99.67