Libvirt: Fsfreeze during live-snapshot of qemu/kvm instances

This blueprint proposes automatic quiesce feature during snapshotting
an image of an instance using qemu-guest-agent and fsFreeze/fsThaw API
in libvirt >= 1.2.5.

bp quiesced-image-snapshots-with-qemu-guest-agent

Change-Id: I37aba48b24dfc2c0188a0eb27cefff15c1ca345a
Merge "Libvirt: Fsfreeze during live-snapshot of qemu/kvm instances"