httpclient's USER_AGENT constant wasn't properly deprecated since
the deprecation was only a comment. Proper deprecation requires use
of warnings/debtcollector and documentation, but since this is a
module symbol there's no way to put out a warning, so it's just
documentation in this case.

bp deprecations

Change-Id: I02c77c690a31eea40935d2756748382abec86867

The comments indicated that creating a HTTPClient without a
session is deprecated, but there was no warning generated.

bp deprecations

Change-Id: I44796cbff95a7bbdd6e7a58e5cfb8360bdae5477

Session.construct() wasn't properly deprecated since the deprecation
was only mentioned in the docstring. Proper deprecation requires use
of warnings/debtcollector and documentation.

bp deprecations

Change-Id: Ieff238aff9d39cfbbb80381b2392c33d0359acb3

There was a FIXME to deprecate ServiceCatalog's region_name
parameter and property. This is now deprecated.

Note that debtcollector isn't used here since the deprecation
happens on ServiceCatalog's __init__() to catch use in
subclasses of ServiceCatalog. ServiceCatalog also has a
factory function that constructs the correct instance and
the factory function always passes region_name, so it's
always using the deprecated kwarg even when region_name
isn't passed to the factory. It's not worth figuring out
how to do this with debtcollector.

bp deprecations

Change-Id: I0e64712474ca2767f3c0ade919359132450f6776

Iterating over a dict results in the keys.

Using the 'in' operator on a dict checks if it's a key.

Change-Id: I6affbfa1a79a9e8c0b5b304078a7a8e4e792eecd

HTTPClient's forwarded session and adapter properties weren't
properly deprecated since the deprecations was only mentioned in
the docstring. Proper deprecation requires use of warnings/
debtcollector and documentation.

bp deprecations

Change-Id: Iea76d7bbc3bdeb13f7fdb097f13e007b4dd85c8d

HTTPClient.request and related methods weren't properly
deprecated since they were only mentioned in the docstrings.
Proper deprecation requires use of warnings/debtcollector and
documentation.

Also, fixed places where the deprecated request method was called.

bp deprecations

Change-Id: I0a16933252937ca046793bb6eb2e5cc5da03c9ae

HTTPClient tenant_id and tenant_name properties weren't properly
deprecated since they were only mentioned in the docstring. Proper
deprecation requires use of warnings/debtcollector and
documentation.

bp deprecations

Change-Id: I3c2f87df14bc9f8ffd82b99919fd1048123d0669

HTTPClient() tenant_id and tenant_name parameters weren't properly
deprecated since they were only mentioned in the docstring. Proper
deprecation requires use of warnings/debtcollector and documentation.

Also fixed a bunch of places in the tests where tenant_id and
tenant_name were still being used despite being deprecated.

bp deprecations

Change-Id: I9c4f596b8ff10aede6c417886638a942cb18044c

httpclient.request() wasn't properly deprecated since it was only
mentioned in a comment. Proper deprecation requires use of
warnings/debtcollector and documentation.

bp deprecations

Change-Id: Id35d64a8b2d536c5de90e398b2a7680fa30881d6