caddy-frontend: Drop obsolete ATS configuration key

proxy.config.snapshot_dir is unavailable since TrafficServer 8.

software/caddy-frontend/buildout.hash.cfg

@@ -62,7 +62,7 @@ md5sum = 975177dedf677d24e14cede5d13187ce
 
 [template-trafficserver-records-config]
 _update_hash_filename_ = templates/trafficserver/records.config.jinja2
-md5sum = 1696321871bb71083550c95d77487602
+md5sum = ab0c9ea9bfe7a63a267331d9e010d0c6
 
 [template-trafficserver-storage-config]
 _update_hash_filename_ = templates/trafficserver/storage.config.jinja2

software/caddy-frontend/templates/trafficserver/records.config.jinja2

@@ -15,7 +15,6 @@ CONFIG proxy.config.env_prep STRING example_prep.sh
 CONFIG proxy.config.alarm_email STRING nobody
 CONFIG proxy.config.syslog_facility STRING LOG_DAEMON
 CONFIG proxy.config.output.logfile STRING traffic.out
-CONFIG proxy.config.snapshot_dir STRING snapshots
 CONFIG proxy.config.admin.user_id STRING {{ '#%s' % os_module.geteuid() }}
 CONFIG proxy.config.admin.number_config_bak INT 0
 LOCAL proxy.local.incoming_ip_to_bind STRING {{ ats_configuration['local-ip'] }}