Add oslo.concurrency to mistral.conf namespace list

This patch adds oslo.concurrency namespace when generating mistral.conf

Signed-off-by: Thomas Goirand <zigo@debian.org>
Change-Id: I0197ea48f0ec559ec29863dd119c3f0ef689701d

tools/config/config-generator.mistral.conf

@@ -4,6 +4,7 @@ wrap_width = 80
 summarize = true
 namespace = mistral.config
 namespace = cotyledon
+namespace = oslo.concurrency
 namespace = oslo.db
 namespace = oslo.messaging
 namespace = oslo.middleware.cors