Remove premature restart of Keystone service during configuration

For simplification purposes, restarting the Keystone service
should wait until after configuring all relevant directives
in keystone.conf.

Change-Id: Id26edc20236953215dd18635fbe143f4bc1bc8da
Closes-Bug: #1258651
(cherry picked from commit 26ac40e2b594a72d807815947db2832f6aa66904)