Cinder list does not filter admin metadata.

For example, if you want to filter by 'readonly' attribute,
you do not get results.
This patch adds the admin metadata for filtering.

Change-Id: Ia2a72776e649abd82160cb13ad63489cc760b190
Closes-Bug: #1311277
Remove unused volume instance_uuid methods

This patch removes a db api call that is only
used in unit tests.

Change-Id: Ic686eacdee21d13f8c7c7a16d7353211abc7579a
Related-Bug: #1255925
Merge "Remove unused volume instance_uuid methods"
Merge "Cinder list does not filter admin metadata."