Remove vestiges of obsolete USE_CUSTOM_THEME setting

playbooks/roles/edxapp/defaults/main.yml

@@ -245,7 +245,6 @@ EDXAPP_FEATURES:
   ENABLE_INSTRUCTOR_ANALYTICS: false
   PREVIEW_LMS_BASE: "{{ EDXAPP_PREVIEW_LMS_BASE }}"
   ENABLE_GRADE_DOWNLOADS: true
-  USE_CUSTOM_THEME: "{{ edxapp_use_custom_theme }}"
   ENABLE_MKTG_SITE: "{{ EDXAPP_ENABLE_MKTG_SITE }}"
   AUTOMATIC_AUTH_FOR_TESTING: "{{ EDXAPP_ENABLE_AUTO_AUTH }}"
   ENABLE_THIRD_PARTY_AUTH: "{{ EDXAPP_ENABLE_THIRD_PARTY_AUTH }}"
@@ -1202,12 +1201,10 @@ worker_core_mult:
   cms: 2
 
 # Stanford-style Theming
-# Turn theming on and off with edxapp_use_custom_theme
 # Set theme name with edxapp_theme_name
 # Stanford, for example, uses edxapp_theme_name: 'stanford'
 #
 # TODO: change variables to ALL-CAPS, since they are meant to be externally overridden
-edxapp_use_custom_theme: false
 edxapp_theme_name: ""
 edxapp_theme_source_repo: 'https://{{ COMMON_GIT_MIRROR }}/Stanford-Online/edx-theme.git'
 edxapp_theme_version: 'master'

playbooks/sample_vars/server_vars.yml

@@ -100,7 +100,6 @@
 #  SUBDOMAIN_COURSE_LISTINGS: false
 #  PREVIEW_LMS_BASE: "{{ EDXAPP_PREVIEW_LMS_BASE }}"
 #  ENABLE_GRADE_DOWNLOADS: true
-#  USE_CUSTOM_THEME: "{{ edxapp_use_custom_theme }}"
 #  ENABLE_MKTG_SITE: "{{ EDXAPP_ENABLE_MKTG_SITE }}"
 #  AUTOMATIC_AUTH_FOR_TESTING: "{{ EDXAPP_ENABLE_AUTO_AUTH }}"
 #  ENABLE_THIRD_PARTY_AUTH: "{{ EDXAPP_ENABLE_THIRD_PARTY_AUTH }}"