Replace tearDown with addCleanup - Part 4

Infra team has indicated that tearDown should not be used and should
be replaced with addCleanup in all places.

All addCleanup methods will be executed even if one of them fails, while
a failure in tearDown method can leave the rest of the tearDown un-executed,
which can leave stale state laying around.

Moreover, tearDown methods won't run if an exception raises in setUp method,
while addCleanup will run in such case.

This patch replaces tearDown with addCleanup or removes redundant tearDown
methods in cinder unit tests.

Implements blueprint replace-teardown-with-addcleanup

Change-Id: I6947eafa419ed7dda53582484090cd5210274f73
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."
Merge "Replace tearDown with addCleanup - Part 4"