[QA] php 5.5 jobs migrating to Jessie

[Antoine Musso]

Hello,

CI has kept Ubuntu Trusty instance solely for Zend PHP 5.5.  Last week I 
managed to build a rough package for Debian Jessie and got them 
provisioned on the instances.

Hence I have started migrating jobs from Trusty to Jessie, testing them 
on all affected repositories as I am doing the change.

I hope to have mostly completed the migration by the end of the week and 
definitely aim at not causing any false failures for developers.

Once it is completed. I will drop the Ubuntu Trusty instances.

Tracking task is:
https://phabricator.wikimedia.org/T161882

-- 
Antoine "hashar" Musso