add performance graphite variables

playbooks/roles/edxapp/defaults/main.yml

@@ -418,6 +418,8 @@ EDXAPP_CORS_ORIGIN_WHITELIST: []
 EDXAPP_CORS_ORIGIN_ALLOW_ALL: false
 # Video Beacon Settings
 CDN_VIDEO_URLS: {}
+PERFORMANCE_GRAPHITE_URL: 'SetPerformanceGraphiteHostName'
+
 
 #-------- Everything below this line is internal to the role ------------
 
@@ -656,6 +658,8 @@ generic_env_config:  &edxapp_generic_env
   MKTG_URL_LINK_MAP: "{{ EDXAPP_MKTG_URL_LINK_MAP }}"
   MKTG_URLS: "{{ EDXAPP_MKTG_URLS }}"
   CDN_VIDEO_URLS: "{{ CDN_VIDEO_URLS }}"
+  PERFORMANCE_GRAPHITE_URL: "{{ PERFORMANCE_GRAPHITE_URL }}"
+
   # repo root for courses
   GITHUB_REPO_ROOT: "{{ edxapp_course_data_dir }}"
   CACHES: