read the comment service shared key from django config

lms/envs/aws.py

@@ -68,4 +68,4 @@ if 'COURSE_ID' in ENV_TOKENS:
     ASKBOT_URL = "courses/{0}/discussions/".format(ENV_TOKENS['COURSE_ID'])
 
 COMMENTS_SERVICE_URL = ENV_TOKENS["COMMENTS_SERVICE_URL"]
-
+COMMENTS_SERVICE_KEY = ENV_TOKENS["COMMENTS_SERVICE_KEY"]

lms/envs/dev.py

@@ -92,6 +92,8 @@ SUBDOMAIN_BRANDING = {
     'harvard': 'HarvardX',
 }
 
+COMMENTS_SERVICE_KEY = "PUT_YOUR_API_KEY_HERE"
+
 ################################ LMS Migration #################################
 MITX_FEATURES['ENABLE_LMS_MIGRATION'] = True
 MITX_FEATURES['ACCESS_REQUIRE_STAFF_FOR_COURSE'] = False   # require that user be in the staff_* group to be able to enroll

lms/lib/comment_client/settings.py

@@ -7,4 +7,7 @@ else:
 
 PREFIX = SERVICE_HOST + '/api/v1'
 
-API_KEY = "PUT_YOUR_API_KEY_HERE"
+if hasattr(settings, "COMMENTS_SERVICE_KEY"):
+    API_KEY = settings.COMMENTS_SERVICE_KEY
+else:
+    API_KEY = "PUT_YOUR_API_KEY_HERE"