Increase failure details for network_basic_ops

Indicate place of failure since network_basic_ops is becoming more complicated

Change-Id: I3f513f34692e77230271d884bee53cc672b5ca40
Don't run extensions list if service isn't available

This commit adds a check to see if the service is available before
running the extension list verification.

Partially implements bp config-verification

Change-Id: I722440cf84a44d9c38536a3421972c1cb837969e
Fix services decorator to use object_storage

Previously the services decorator used the keyword object to denote that
the test would use swift. However, everywhere else object_storage is used.
This commit makes the usage consistent by switching it to object_storage.

Change-Id: I69edf44a9b3b731616f1faeb240a691a187df845
Fix attach_interfaces tests of Nova v3

Tempest's interfaces_client calling Nova "os-interface" v2 API was fixed
in I3db0381d48919c62f3f3c6d60fc14cf4dee9c4a3 .
However, there is still a same bug about v3 API. This commit fixes it.

NOTE: API and POST parameter was changed in Nova v3.
 v2: {API: os-interface, parameter: interfaceAttachment}
 v3: {API: os-attach-interfaces, parameter: interface_attachment}

Change-Id: I7b5b9419366d779bf07dd19383f28550b9d6f369
Closes-Bug: #1271642
Merge "Fix services decorator to use object_storage"
Merge "Increase failure details for network_basic_ops"
Merge "Don't run extensions list if service isn't available"
Merge "Fix attach_interfaces tests of Nova v3"