Add vagrant-persistent-storage to OSX setup.
Add vagrant-persistent-storage to OSX setup.

Just reduces the likelihood of errors like the other plugin installs
that don’t always work inline within the same Vagrantfile execution.

robw/precip,clwdev/precip,Xenza/precip,robw/precip,Xenza/precip,robw/precip,robw/precip,Xenza/precip,Xenza/precip,clwdev/precip,clwdev/precip,clwdev/precip