Handle endpoints with versions consistently

When using the cli the Glance client wraps the endpoint in a 'strip
version' function. This means that endpoints of the following forms can
both be used:

https://region-x.images.example.com:443/v1
https://region-x.images.example.com:443

When calling the client library directly (as Ceilometer does) however
only endpoints of the second form work. The cli and library should handle
the two cases consistently.

Addresses bug 1243276.

Change-Id: Ice7b581fee32540a7057ba47433a10166a3caed2
Using common method 'bool_from_string' from oslo strutils

Using common method 'bool_from_string' from oslo strutils to replace
utils.string_to_bool.

partially implements blueprint common-client-library-2

Change-Id: I23924db3000feadcfe823c6cc979ea9752a13fa9
Merge "Handle endpoints with versions consistently"
Merge "Using common method 'bool_from_string' from oslo strutils"