beta: allow ssh from gallium on parsoid instance

I need deployment-parsoid2 to be made a Jenkins slave, since Parsoid
class adds ferm rule, I get to explicitly allow ssh from gallium
(jenkins master).

Will then made the instance a Jenkins slave and made it execute an
update of Parsoid whenever a change is made against the repositories
mediawiki/services/parsoid{,/deploy}

Change-Id: I21d28474cf48390b052d6171978abb86550db167