Drop validation of service name which is not implemented for
the other daemons. This allows us to simplify handling of the provided
service name.
Also remove the "dead" support for standalone keystone service in
CentOS/RHEL because the service is no longer available in these
operating systems.
Change-Id: I4aacfc55e43bc15a1e9f821353633d651dc29dfa
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>