Fetch a working trusty box on VMWare Fusion provider

MediaWiki-Vagrant wasn't working under Hashi's proprietary
VMWare Fusion provider because the configuration is fetching
from a VirtualBox-only box source.

Added conditional configuration for virtualbox (setting the
one we were using unconditionally before) and vmware_fusion
(fetching puphpet's trusty box as reported working on bug).

Also included some VM option setting from the config patch
on the bug, adjusted for current version/format.

Based on config patch from bug:
https://bugzilla.wikimedia.org/attachment.cgi?id=15245

Bug: 59904
Change-Id: Ia34ec94e286435a381e8ef8f71289530b9cf5067
Merge "Fetch a working trusty box on VMWare Fusion provider"