Support oslo-rootwrap in lib/cinder

Make lib/cinder support both cinder-rootwrap (current case) and
oslo-rootwrap (future case) to handle the Cinder transition towards
oslo-rootwrap usage peacefully.

Related blueprint:
https://blueprints.launchpad.net/cinder/+spec/cinder-oslo-rootwrap

Change-Id: I663986304bd74cb6d72d51c553540fb5f9db1d1d
Merge "Support oslo-rootwrap in lib/cinder"
XenAPI: Update DomU to Ubuntu Saucy

Driven by a race condition in LVM being hit in the tempest
tests.  This is a locking race between a file lock and a
semaphore which is fixed in 2.02.96-5.

Change-Id: I8a8c215c90a0602288292ffd06b7694d2db6219e
Fix xenapi functions' tests

The tests got outdated, this fix makes the tests pass again.

Change-Id: Iadddfbf34bf79ba455811645e766c2f3d0fcca84
Workaround missing zip snapshot

At the moment, xenserver installation depends on github snapshots.
Unfortunately, git.openstack.org does not have that capability. This
fix includes:

 - Exit with error code, if a download fails
 - create proper urls, even if they are using the git protocol
 - set git base to github - so we are able to do snapshots

Fixes bug: 1259905

Change-Id: I8d0cf8bf8abb16ee0a4b138a6719409c75e7a146