Keep track of gerrit.war and golden_site versions

Also add some log during tests preparation.
This patch will redownload gerrit.war unless you rename it:

    mv .gerrit/gerrit.war .gerrit/gerrit-2.8.5.war

Change-Id: I0f0a6cf7cfb70778d47a0fcbf1f09c5d292cd425
Merge "Keep track of gerrit.war and golden_site versions"