Fixes cinder volume delete on Windows

Because of the fact that an iSCSI target is not created anymore
at volume creation time, not all volumes will have a corresponding
target. For this reason, when removing an iSCSI target we must
first check if the target actually exists.

Change-Id: I8e571397df6d9a2eeb05e883b7da8494d4bfa1ad
Closes-Bug: #1299124
GlusterFS: Delete volume-<uuid>.info file when volume is deleted.

glusterfs creates a file named volume-<uuid>.info to hold volume
data, mapping cinder snapshot UUIDs and filenames. When the
volume and its associated snapshots are both deleted, this file
remains. This patch deletes the volume-<uuid>.info (if one exists)
when the volume is deleted.

Change-Id: Iefc8bd4768b30a75c648c4689d935daeab3afe98
Closes-Bug: #1299182
Allow deprecated volume update keys in v2

Keys like display_name and display_description were deprecated for other
actions in v2 like creating volumes, so for consistency they should work
with updating.

DocImpact
Closes-Bug: #1301172
Change-Id: I19bc7c85352578bb57fa9fdaf1817f78e0ee2f2a
Merge "Fixes cinder volume delete on Windows"
Merge "GlusterFS: Delete volume-<uuid>.info file when volume is deleted."
Merge "Allow deprecated volume update keys in v2"