The `tempurl` subcommand's second positional argument is called
`seconds` and has heretofore interpreted as the number of seconds for
which the tempURL should be valid, counting from the moment of running
the command. This is indeed a common, if not the most common,
use-case. But some users, occasionally, might want to generate a tempURL
that expires at some particular ("absolute") time, rather than a
particular amount of time relative to the moment of happening to run the
command. (One might make an analogy to the way in which Swift's expiring
object support supports an `X-Delete-At` header in addition to
`X-Delete-After`—and it's the former that must be regarded as
ontologically prior.) Thus, this commit adds an `--absolute` optional
argument to the `tempurl` subcommand; if present, the `seconds` argument
will be interpreted as a Unix timestamp of when the tempURL should be
expire, rather than a duration for which the tempURL should be valid
starting from "now".

Change-Id: If9ded96f2799800958d5063127f3de812f50ef06

Some improvements to the tests for staggered download
that were added in [1].

[1] Ie737cbb7f8b1fa8a79bbb88914730b05aa7f2906

Change-Id: Ib999bc7bd198c1d9c217c57501f751e854d4c6ad

This patch adds exception logging to the swift service API. Each
operation that results in failure of any operation will now log
the exception as well as report a timestamp and full stack trace
in the results returned by the service API calls.

Change-Id: I7336b28354e7740ea7d048bdf355e3c1a1b4436c

When a caller passes an os_options dict to the Connection class
constructor, the constructor may modify the os_options dict,
which can surprise the caller if they re-use the os_options
dict. Specifically the os_options tenant_name and object_storage_url
may be modified, and the changed values would then leak through to a
subsequent Connection constructed using the same os_options dict.

This fix simply constructs a new dict from the supplied os_options.
The patch also adds a test that covers this and also verifies that
a preauth_url passed as a keyword arg to Connection() will take
precedence over any object_storage_url in an os_options parameter.

Closes-Bug: 1488070
Change-Id: Ic6b5cf3ac68c505de155619f2610be9529e15432

Add client changes to allow accessing alternative
reseller_prefixes via a service token.

ie client changes for this server side spec:
 https://review.openstack.org/#/c/105228

We assume that the service storage url has been passed in
as a preauthurl.

We rely on get_auth preserving this url.

Change-Id: I1cfda178f0b6c8add46cfebd6bf38440caae2036