Ability to set lock_path

PROD-34037

Change-Id: I0b462d1debf0fe57192cca3b63cc550560f722c6
diff --git a/README.rst b/README.rst
index 2ed2f57..6c9c9e4 100644
--- a/README.rst
+++ b/README.rst
@@ -31,6 +31,8 @@
         bind:
           api:
             address: 127.0.0.1
+        concurrency:
+          lock_path: '/var/lib/designate'
         database:
           engine: mysql
           host: 127.0.0.1