common.config: change X11 server selection logic for a few hosts
common.config: change X11 server selection logic for a few hosts

Only applies to the QA Farm.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp