Correct the name of the ansible vars.

playbooks/roles/edxapp/defaults/main.yml

@@ -607,10 +607,10 @@ generic_env_config:  &edxapp_generic_env
   PRESS_EMAIL: $EDXAPP_PRESS_EMAIL
   PLATFORM_TWITTER_ACCOUNT: $EDXAPP_PLATFORM_TWITTER_ACCOUNT
   PLATFORM_FACEBOOK_ACCOUNT: $EDXAPP_PLATFORM_FACEBOOK_ACCOUNT
-  PLATFORM_TWITTER_URL: "{{ PLATFORM_TWITTER_URL }}"
-  PLATFORM_MEETUP_URL: "{{ PLATFORM_MEETUP_URL }}"
-  PLATFORM_LINKEDIN_URL: "{{ PLATFORM_LINKEDIN_URL }}"
-  PLATFORM_GOOGLE_PLUS_URL: "{{ PLATFORM_GOOGLE_PLUS_URL }}"
+  PLATFORM_TWITTER_URL: "{{ EDXAPP_PLATFORM_TWITTER_URL }}"
+  PLATFORM_MEETUP_URL: "{{ EDXAPP_PLATFORM_MEETUP_URL }}"
+  PLATFORM_LINKEDIN_URL: "{{ EDXAPP_PLATFORM_LINKEDIN_URL }}"
+  PLATFORM_GOOGLE_PLUS_URL: "{{ EDXAPP_PLATFORM_GOOGLE_PLUS_URL }}"
   ORA2_FILE_PREFIX: $EDXAPP_ORA2_FILE_PREFIX
   FILE_UPLOAD_STORAGE_BUCKET_NAME: $EDXAPP_FILE_UPLOAD_STORAGE_BUCKET_NAME
   FILE_UPLOAD_STORAGE_PREFIX: $EDXAPP_FILE_UPLOAD_STORAGE_PREFIX