... because api/os_region_name is not set since [1].
This patch also fixes incorrect lookup about domain parameters.
This patch also removes useless and incorrect handling about keystone
version, so that domain parameters are correctly set.
[1] c2d618cae70ba1be7dd8496ce7665ac3abaf8775
Change-Id: Idaa1c767e8cab645567b920dc9d377abf509ec54