Add support for configuring libvirt VM clock and timers
Add support for configuring libvirt VM clock and timers

There are a number of time sources made available to guests,
each of which have a number of configurable policies. This
introduces config APIs for the libvirt domain XML to configure
the clock time sources

Change-Id: Ic5047b02b4753f20bb9a63e85130d84258df7a28
Signed-off-by: Daniel P. Berrange <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

n0ano/gantt,n0ano/gantt