Fix CA certificate handling

If --os-cacert was passed to the cli the following error was
triggered: "cafile must be None or a byte string". This is
because 'load_verify_locations' requires a byte string to
be passed in.

We fix this by explicitly converting the argument to a byte
string.

We do this in 'VerifiedHTTPSConnection' rather than sooner, eg
during arg handling, as it will no longer be required should we
move to a different http library (eg requests).

Fixes bug 1301849.

Change-Id: I9014f5d040cae9f0b6f03d8f13de8419597560cb
Add license to setup.cfg

Glance client's setup.cfg was missing the license attribute. This commit
adds it to make it consistent with other clients and server libraries.
The value of the license attribute reflects the license in the LICENSE
file.

Change-Id: Ia2e8c3be4fe7eaf0db5eb397646068c83076c2ff
Add missing classifiers

This commit adds 2 more classifiers to setup.cfg. An environment
classifier that specifies glanceclient is a console tool and a
development classifier that specifies it is production ready.

Change-Id: Ia60ea76798503b0a729c384298f1a633d695a1ab
Add wheels section to the setup.cfg

Glance client's setup.cfg was missing the wheels section. This commit
adds it and makes the client's setup.cfg consistent with other clients.

Change-Id: I16030c0379dae3c3c07bd73f09798c2160310811
Merge "Fix CA certificate handling"
Merge "Add license to setup.cfg"
Merge "Add missing classifiers"
Merge "Add wheels section to the setup.cfg"
Added release notes for 0.13.0

Change-Id: I51374661a5ce58cd2a970a75893b1251ab6e176b