Replace unused oslo.service options

In threading mode the options implemented in oslo.service are not used,
in favor of the options imported from cotyledon.

Change-Id: I62fe8b6b721359d2f479028ef3e3eae854fa8283
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

tools/config/config-generator.mistral.conf

@@ -3,6 +3,7 @@ output_file = etc/mistral.conf.sample
 wrap_width = 80
 summarize = true
 namespace = mistral.config
+namespace = cotyledon
 namespace = oslo.db
 namespace = oslo.messaging
 namespace = oslo.middleware.cors
@@ -12,4 +13,3 @@ namespace = keystonemiddleware.auth_token
 namespace = oslo.log
 namespace = oslo.policy
 namespace = oslo.service.sslutils
-namespace = oslo.service.service