Configure TCP Keep-Alive for certain Sessions
Configure TCP Keep-Alive for certain Sessions

If the user creates a keystoneclient.session.Session without passing a
custom session, we will enable TCP Keep-Alive for the requests session
used by keystoneclient's Session.

novaclient and other clients can experience hung TCP connections. Most
clients use keystoneclient's session and will need this merged here
before they can make use of it in their projects.

Change-Id: Ib70a8b3270d2492596b9fb8981b8584b85567a9c
Closes-bug: 1323862

sileht/keystoneauth,jamielennox/keystoneauth,citrix-openstack-build/keystoneauth