Removes volumes redefinition in fake nova_client

Reasons:
- The redefinition of nova_client.volumes was making it,
  nova_client.volumes.volumes, if we needed to call the volume APIs
  from nova_client.
- nova_client.volumes is already defined when defining "class FakeClient".

Changes:
- Removes redefinition of nova_client.volumes.

Change-Id: I5981d461e5a0fd000214c35d5d0be58d86d6d368
Closes-Bug: #1292457
Resolves volume resize issue

Reasons:
- Cinder APIs are not able to complete the detach/attach properly with
  nova instance.
- resize2fs is not proceeding with "-f" and "-n" options.

Changes:
- Used nova-volume attach-detach APIs instead of cinder APIs.
- Updated e2fsck to use -p option to complete the e2fsck action so that
  resize2fs could proceed.
- Updated tests as per replaced Nova APIs instead of Cinder APIs.

Change-Id: I40f1dc8ca04b3bfcc4eae910515fcedf922c1a9e
Closes-Bug: #1291896
Add scheduled tasks to the API
https://review.openstack.org/#/c/73702/
modify "Add scheduled tasks to the API"
Merge branch 'master' of https://github.com/wrongfan/trove