Merge pull request #1899 from edx/feanil/fix_typo

Fix typo.

playbooks/roles/edxapp/defaults/main.yml

@@ -645,7 +645,7 @@ generic_env_config:  &edxapp_generic_env
   BOOK_URL:  "{{ EDXAPP_BOOK_URL }}"
   PLATFORM_NAME: "{{ EDXAPP_PLATFORM_NAME }}"
   STUDIO_NAME: "{{ EDXAPP_STUDIO_NAME }}"
-  STUDIO_SHORT_NAME: "{{ EXAPP_STUDIO_SHORT_NAME }}"
+  STUDIO_SHORT_NAME: "{{ EDXAPP_STUDIO_SHORT_NAME }}"
   CERT_QUEUE:  'certificates'
   LOCAL_LOGLEVEL: "{{ EDXAPP_LOG_LEVEL }}"
   # default email backed set to local SMTP