Setup pools to keep guests on same disk (for teuthology runs).

Looks to see if the /srv/libvirtpool/ dir was setup during when
the machine was imaged and loop through directories/mount points
and create libvirt pools for use with teuthology to keep guests
on their own disk in JBOD mode.

Signed-off-by: Sandon Van Ness <sandon@inktank.com>