Merge pull request #2872 from edx/mzfr/preview-tnl4073

Removing HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS to make preview domain…

playbooks/roles/edxapp/defaults/main.yml

@@ -143,9 +143,6 @@ EDXAPP_ENABLE_CREDIT_API: false
 # Settings for enabling and JWT auth for DRF API's
 EDXAPP_ENABLE_JWT_AUTH: false
 
-EDXAPP_MODULESTORE_MAPPINGS:
-    'preview\.': 'draft-preferred'
-
 EDXAPP_GIT_REPO_DIR: '/edx/var/edxapp/course_repos'
 EDXAPP_GIT_REPO_EXPORT_DIR: '/edx/var/edxapp/export_course_repos'
 
@@ -826,7 +823,6 @@ generic_env_config:  &edxapp_generic_env
   CAS_SERVER_URL: "{{ EDXAPP_CAS_SERVER_URL }}"
   CAS_EXTRA_LOGIN_PARAMS: "{{ EDXAPP_CAS_EXTRA_LOGIN_PARAMS }}"
   CAS_ATTRIBUTE_CALLBACK: "{{ EDXAPP_CAS_ATTRIBUTE_CALLBACK }}"
-  HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS: "{{ EDXAPP_MODULESTORE_MAPPINGS }}"
   UNIVERSITY_EMAIL: "{{ EDXAPP_UNIVERSITY_EMAIL }}"
   PRESS_EMAIL: "{{ EDXAPP_PRESS_EMAIL }}"
   SOCIAL_MEDIA_FOOTER_URLS: "{{ EDXAPP_SOCIAL_MEDIA_FOOTER_URLS }}"