caddy-frontend: Drop etc/promise directory reference

caddy-frontend master partition does not implement any promise in etc/promise,
all is migrated to etc/plugin

software/caddy-frontend/buildout.hash.cfg

@@ -22,7 +22,7 @@ md5sum = c801b7f9f11f0965677c22e6bbe9281b
 
 [template-apache-frontend]
 filename = instance-apache-frontend.cfg.in
-md5sum = 04f7b96a65c304a8a5bf6265d62bb05a
+md5sum = 6abe3aae72a83ef90e484d00cc70490d
 
 [template-apache-replicate]
 filename = instance-apache-replicate.cfg.in

software/caddy-frontend/instance-apache-frontend.cfg.in

@@ -60,7 +60,6 @@ log = ${:var}/log
 run = ${:var}/run
 service = ${:etc}/service
 etc-run = ${:etc}/run
-promise = ${:etc}/promise
 plugin = ${:etc}/plugin
 
 ca-dir = ${:srv}/ssl
@@ -260,7 +259,6 @@ extra-context =
     section caddy_configuration caddy-configuration
     key monitor_base_url monitor-instance-parameter:monitor-base-url 
     key plugin_directory directory:plugin
-    key promise_directory directory:promises
     key report_directory directory:bin
     key bin_directory :bin_directory
     key enable_http2_by_default configuration:enable-http2-by-default