syntax fix in README

Change-Id: I2b73a758fc795e0d581d1c321d308cb255e90dec
diff --git a/README.rst b/README.rst
index 0821b40..ddf734c 100644
--- a/README.rst
+++ b/README.rst
@@ -349,7 +349,7 @@
 .. code-block:: yaml
 
     kubernetes:
-      master
+      master:
         ...
         storage:
           engine: glusterfs
@@ -371,7 +371,7 @@
 .. code-block:: yaml
 
     kubernetes:
-      master
+      master:
         ...
         namespace:
           kube-system:
@@ -405,7 +405,7 @@
 .. code-block:: yaml
 
     kubernetes:
-      master
+      master:
         ...
         registry:
           secret: