adds tests for CINDER encryption volume-type APIs

This patch adds the JSON tests for CINDER encryption volume-type V1 APIs.
It also adds the JSON clients for following APIs :
1. cinder encryption-type-delete

Change-Id: I20a68684f950fe36653eb4304edb56e244867ca3
Wait for server activations for the updated servers

In test_list_servers_by_changes_since, Tempest tries to get a server
list with changes-since parameter. The test expects we can get all
servers with the parameter, but sometimes we could not get it and the
gate tests failed.
On "create a server" API Nova creates a DB record of the server as
the first step, then updates the record by each step(scheduling,
networking, etc.) during the server creation. If the test runs just
after the DB record creation, the record is not updated and "get a
server list" API with changes-since parameter does not contain the
server. As the result, the test fails.

This patch makes the test wait for server activations to avoid the
non-updated servers.

Change-Id: I380ae2030da794c4f8fcfd6347f9cbe7f75b5c28
Closes-Bug: #1254238
Merge "adds tests for CINDER encryption volume-type APIs"
Remove the list_servers_since_test

This test is mostly just a very good way to add new failures. There
are subtleties on the timestamping of servers which means that this
can often return the wrong number of servers. Because of this we
should just delete the test.

If we want something like this we should create a much more sane setup
that includes getting all the servers, determinging some subset that
the filter should return, fetching those, and getting the count.

Change-Id: I5c08ef031043229b76a6800eeaab6d418fc4614f
Merge "Remove the list_servers_since_test"
Merge "Wait for server activations for the updated servers"