If a request fails but the response contains a "Retry-After",
the cinder client should wait the amount of time and then retry.
Cinder client should report a warning to user and continue with
retry, so that user can cancel the operation if not interested
in retry. The value in "Retry-After" header will be in seconds
or GMT value, client should handle both the cases.
How many times client should retry will be controlled by user
through "--retries" argument to cinder api example,
$ cinder --retries 3 availability-zone-list
If request was not sucessful within the retries, client should
raise the exception.
Change-Id: I99af957bfbbe3a202b148dc2fcafdd20b5d7cda0
Partial-Bug: #1263069
f8eef18297