Gerrit 2.5.4 upgrade

[Itamar Heim]

just to sum up the highlights of upgrade from June 9th:

- Gerrit was upgraded to 2.5.4

- new REST API
http://gerrit-documentation.googlecode.com/svn/ReleaseNotes/ReleaseNotes-2.5.html#_rest_api

- Custom Dashboards
http://gerrit-documentation.googlecode.com/svn/Documentation/2.5/user-custom-dashboards.html

- the inline email are now part of gerrit (we used to run a patched 2.4
   version with them)

- new prolog submit rules (still considering how can be best used)
http://gerrit-documentation.googlecode.com/svn/Documentation/2.5/prolog-cookbook.html

- the mirroring plugin (to github.com/oVirt) is now a plugin (Thanks
   David)

- looking forward to gerrit 2.6 upgrade which promises "42x improvement
   on git clone and git fetch"

(I also remember it was supposed to improve copying approval flags on 
rebase, but couldn't find the reference).

Thanks,
    Itamar