unhardcode reauth method for rocky

Change-Id: I8368c9050fea798a2f19e5d6818455135fd8cb4a
Related-Prod: https://mirantis.jira.com/browse/PROD-27017
diff --git a/heat/files/rocky/heat.conf.Debian b/heat/files/rocky/heat.conf.Debian
index d66d3ee..3e40566 100644
--- a/heat/files/rocky/heat.conf.Debian
+++ b/heat/files/rocky/heat.conf.Debian
@@ -39,6 +39,9 @@
 # '' - <No description provided>
 # trusts - <No description provided>
 #reauthentication_auth_method =
+{%- if server.reauthentication_auth_method is defined %}
+reauthentication_auth_method = {{ server.reauthentication_auth_method }}
+{%- endif %}
 
 # Subset of trustor roles to be delegated to heat. If left unset, all roles of
 # a user will be delegated to heat when creating a stack. (list value)