Install keyring on static for keystoneclient

Python-keystoneclient needs relatively new keyring to be installed,
but it is not listed in keystoneclient requirements. Work around this by
manually installing keyring via pip at the latest version.

Change-Id: Ib3b67c3cdd622117f6aee72d07333366cd93657f
Merge "Install keyring on static for keystoneclient"