This change adds support for SSL parameters of [keystone_auth] section.
Note:
Management of [keystone_auth] parameters is removed from the authtoken
class. However this is effectively same, because Magnum reads
[keystone_authtoken] parameters in case [keystone_auth] parameters are
not set.
Change-Id: I3acc6a64b7789633ab068d8bbdcb2b9c11f2fb2d