Use cached volumes in REST API extensions

This patch caches db volumes in the core volumes API so that they can be
used in the host and tenant attribute API extensions in order to lower
the response time by avoiding costly individual db queries for each
volume in the REST API contributions.

Change-Id: Ie0cbe929379df32fddbdce1953f13b6f26208bff
Partial-Bug: #1197612
Merge "Do not remove volume silently if GPFS is unmounted"
Merge "Report zero capacity if GPFS is unmounted"
Merge "RequestContext initialization failed in cinder."
Do not allow bad keys while updating quota

Raise 400 (bad request) error instead of 200 (ok) if bad keys
are passed to the update quota request

Closes-Bug: #1248815

Change-Id: Iaefaa4961dd3783dfab15f843cbb2dcb12195a7d
Merge "Nexenta: Remove snapshot after volume-clone deletion."
Imported Translations from Transifex

Change-Id: I8893400d375faefcb59c69f4ed729ecf5e8fe7d3
Merge "Add call to retrieve image metadata for volumes in bulk"
Merge "Retrieve volume image metadata using single query"
Merge "Fail when image is bigger than the volume"
Merge "Imported Translations from Transifex"
Merge "Remove duplication of ISCSIDriver in ISERDriver"
Merge "Nexenta iSCSI driver: extend volume stats of _update_volume_stats"
Merge "Support volume_readonly_update using XML format"
Merge "Do not allow bad keys while updating quota"
Remove the use of common.uuidutils.gen_uuid

There's a movement to remove gen_uuid from the
openstack common.  This change removes it's use
from Cinder and just puts the call inline.

Change-Id: I07329bab9553e15e498ddbda3848d50b8f48fd53
Merge "Don't use deprecated module commands"
Adds extend volume to Dell EqualLogic Driver

Adds extend_volume support to the Dell EqualLogic Driver

Change-Id: I416c73248f1813a805dcca4d70ad6cbc91d78f7d
Implements: blueprint eql-extend-vol-support
Merge "Remove the use of common.uuidutils.gen_uuid"
Merge "Nexenta NFS driver refactoring"