Always use sudo -H when pip installing

Recent versions of pip will create ~/.cache if it doesn't already exist.

If this happens while running "sudo pip" the resulting dir will be owned
by root and 700 - which breaks anything else on the system that wants to
use ~/.cache

I *think* this finds all instances of "sudo pip" in this repo and fixes
them to use -H. This should mean they always run in the right ~

Change-Id: I47ddb3b591df6ac2100f09b38c9b8a03cb1ba1ff
closes-bug: #1405732