Make it clearer that hyphen replacement is not automatic

Change-Id: I54cb2e723ec3cb0f01cfebcef4ec385c166fb5e4

ansible/group_vars/all/kolla

@@ -289,9 +289,9 @@ kolla_build_blocks: {}
 # Dict mapping image customization variable names to their values.
 # Each variable takes the form:
 # <image name>_<customization>_<operation>
-# Hyphens in the image name are replaced with underscores. The customization is
-# most commonly packages. The operation should be one of override, append or
-# remove. The value should be a list.
+# Hyphens in the image name must be replaced with underscores. The
+# customization is most commonly packages. The operation should be one of
+# override, append or remove. The value should be a list.
 kolla_build_customizations: {}
 
 ###############################################################################

ansible/roles/kolla-build/defaults/main.yml

@@ -33,9 +33,9 @@ kolla_build_blocks: {}
 # Dict mapping image customization variable names to their values.
 # Each variable takes the form:
 # <image name>_<customization>_<operation>
-# Hyphens in the image name are replaced with underscores. The customization is
-# most commonly packages. The operation should be one of override, append or
-# remove. The value should be a list.
+# Hyphens in the image name must be replaced with underscores. The
+# customization is most commonly packages. The operation should be one of
+# override, append or remove. The value should be a list.
 kolla_build_customizations: {}
 
 # Free-form extra configuration for kolla-build.

etc/kayobe/kolla.yml

@@ -109,9 +109,9 @@
 # Dict mapping image customization variable names to their values.
 # Each variable takes the form:
 # <image name>_<customization>_<operation>
-# Hyphens in the image name are replaced with underscores. The customization is
-# most commonly packages. The operation should be one of override, append or
-# remove. The value should be a list.
+# Hyphens in the image name must be replaced with underscores. The
+# customization is most commonly packages. The operation should be one of
+# override, append or remove. The value should be a list.
 #kolla_build_customizations:
 
 ###############################################################################