adding link to ovirt code review how-to to gerrit's header

I think it will be usefull to add some info to gerrit's header like a link to "how to code review in oVirt" as I'm seeing contributers missing basic stuff, like using the formatter and so on. I'm attaching a sample header html which have links to our code revbiew wiki. just place it under gerrit's '$site_path'/etc/GerritSiteHeader.html . Also here's the documentation for it [1] [1] http://gerrit.ovirt.org/Documentation/config-headerfooter.html Thanks, Roy