Add pants_bootstradir and pants_configdir to options bootstrapper.

Review Request #1835 - Created Feb. 26, 2015 and submitted

Mateo Rodriguez
benjyw, jsirois, zundel

Make these values available to all classes plumbed with
the options system. There are two OSS places that directly use
pantsboostrapdir: binary_utils and in the ivy boostrapper.
So as config access is removed from those classes, then
they can convert to getting the pants_bootstrapdir from the options
as well.

Removed the expanduser call from the ivy bootstrapper as
it is now redundant. The expanduser happens in the
build_environment.get_cachedir() call that sets
pants_bootstrapdir globally.

Travis is baking (and it is gonna be awhile...):

John Sirois
Mateo Rodriguez
Eric Ayers
Mateo Rodriguez
Mateo Rodriguez
Review request changed

Status: Closed (submitted)