When using stream=True, we need to make sure we release a connection
back to the connection pool to avoid warnings clogging up the logs. We
can do this by releasing the connection once we've read all the content
from the response. In situations where stream=False, requests already
does this for us.

Related-bug: 1424732
Closes-bug: 1341777
Change-Id: Id1c72ad86135a49d4b985992d788736b65f7dbda

Changed existing code to calculate the MD5 of the object
during the upload stream. Checks this MD5 against the etag
returned in the response.
An exception is raised if they do not match.

Closes-Bug: 1379263

Change-Id: I6c8bc1366dfb591a26d934a30cd21c9e6b9a04ce

Missing cacert parameter in get_auth_1_0() and it makes requests_args['verify']
is True in default(likes "swift --os-cacert ssl.crti list").
The requests_args['verify'] should be a ca-certificate file name("ssl.crt").

Change-Id: Id3110f3818f55922ad19eeb1ead80fface824009
Closes-Bug: 1418473

If you specify a token and storage url when creating a Connection,
regardless of the auth api version the first request will be made
directly to swift.  You can either provide a preauthurl and preauthtoken
or fall back to os_options' object_storage_url and auth_token keys
(exposed as --os-storage-url and --os-auth-token on the command line or
OS_STORAGE_URL and OS_AUTH_TOKEN in the environment).

If a _retry wrapped request on a Connection fails because of invalid
authentication (401) the Connection's cached token and url will be
invalidated.  If the Connection's retries attribute is > 0 the
subsequent attempt will call get_auth to refresh the token, but the
pre-configured storage_url will always be re-used.  This is consistent
with current auth v2 behavior and less surprising for auth v1.

The pre-existing, but previously undocumented behavior/interface of
get_auth would override the storage_url returned by the auth service if
the 'os_storage_url' option was provided in the os_options dict.  To
ensure that this behavior is consistent across auth v1 and v2 from the
command line and when using the Connection class as a library - the
preauthurl is stashed in the os_options dict when provided.

Improved Connection.get_capabilities storage_url handling to better
support the consistent behavior of a preauthurl/object_storage_url on
the connection regardless of auth version.

Fixed up some test infrastructure to enable setting up and testing
multiple requests/responses.

Change-Id: I6950fb73f3e28fdddb62760cae9320e2f4336776

Swiftclient hangs forever without any reasonable hint if someone
uses a recent version of swiftclient together with auth version
2 or later. The reason for this is the sys.exit() call in a thread
- the main thread never exists, and swift just waits forever.

Raising a ClientException instead of calling sys.exit() fixes this
and returns the desired information back to the user.

Change-Id: I1fdff85da2dd4b883d337d6098b1695e448d6f2b

keystoneclient isn't adding a NullHandler to its logger,
so we see 'No handlers could be found for logger...'
messages when using the swift cli with keystone auth.

Since keystoneclient follows the usual pattern of
naming loggers  from module name, we can add a
NullHandler to the 'keystoneclient' logger to handle
any logging from the library.

Note that this makes no change to keystoneclient
logging being emitted when using 'swift --debug'
or 'swift --info'.

No test because I am not sure how to usefully
test this without ending up just testing a mock
of keystoneclient.

Change-Id: Ic81cf8e5a590ae9224d35e3a5b1c5f2a8c33835a

Also move it to a module level function.
Change-Id: I2da64876815619a6db7ff208061df2191767806c