Use error instead of warning to log mount exc

Gluster's driver uses warning to log mount exceptions. This patch
replaces that warning with an error message.

Change-Id: I54a10ec8abf460ca9ff7bb009b8d702cfad0fed0
Closes-Bug: #1317573
Ensure metadata is saved before updating volume status

This patch ensures the volume metadata is saved to
the snapshot metadata before updating the status
of the snapshot to be available.

Change-Id: Iada010520dc3c086fcd410a6c7fd152cf4a31561
Closes-Bug: #1310991
Only create volume with an active image

1. Currently cinder doesn't check whether the image is active
when create volume with an image id, we can even create volume
with a deleted/saving/queued image.

2. For deleted image, it only happened when using admin credentials.

When using non-admin credentials, it returned an error that image
is not found by using 'glance image-show' on a deleted image, which
is expected. Also when creating a volume from this deleted image,
it returned  a 404 error upfront. This again is the expected result.

When using admin credentials, we can view the details of deleted image
with 'glance image-show'. If create a volume out of an image ID (which
is now deleted), the operation succeeds, but the volume is left in
'error' state.

3. This accounts for a bug(he volume shouldn't be created) and should be fixed.

Change-Id: If4f59695fbf6636778d0d352aef28d90bb45ee91
Closes-Bug: #1302621
Merge "Only create volume with an active image"
Merge "Ensure metadata is saved before updating volume status"
Merge "Use error instead of warning to log mount exc"