Terraform: remove -rc suffix (elementary#523)

Merge once we're ready to spin a release ISO, before making a stable release.

Author: cassidyjames

etc/terraform-stable-azure.conf

@@ -30,7 +30,7 @@ HWE_X11="no"
 INCLUDE_APPCENTER=""
 
 # suffix for generated .iso files
-OUTPUT_SUFFIX="-rc"
+OUTPUT_SUFFIX=""
 
 # folder suffix for the package lists to use
 PACKAGE_LISTS_SUFFIX="default"