Changed debug instance prefix to "debug-instance."

Due to "_" being an invalid character for hostnames for CAs.

group_vars/all/vars.yml

@@ -32,7 +32,7 @@ backup_mysql_database_scripts_directory: "{{ backup_scripts_directory }}/mysql_d
 # Other variables will need to be adjusted if both instances run on the same server
 is_debug_instance: no
 delete_debug_dns_entries: "{{ not is_debug_instance }}"
-debug_domain: "_transfer.{{ domain }}" # used if is_debug_instance / on "debug mode", should only prefix domain
+debug_domain: "debug-instance.{{ domain }}" # used if is_debug_instance / on "debug mode", should only prefix domain
 effective_domain: "{{ is_debug_instance | ternary(debug_domain, domain) }}"
 
 global_local_user: "{{ lookup('env', 'USER') }}"