Make AvailabilityZone parameter available to nova create

Looks for the AvailabilityZone property in the instance's
resource section. For example:

"Resources" : {
  "Properties": {
    "AvailabilityZone" : "nova",
...

Fixes bug #1096006

Change-Id: I3333b5f909b27e53f6985713de58dd30efc1a80a
Signed-off-by: Jeff Peeler <jpeeler@redhat.com>
Merge "Make AvailabilityZone parameter available to nova create"