Fixed Docker issues for discovery service

- Corrected WSGI package path
- Using a single database user

docker/build/discovery/ansible_overrides.yml

@@ -3,4 +3,5 @@ discovery_gunicorn_host: 0.0.0.0
 DISCOVERY_MYSQL: 'db'
 DISCOVERY_DJANGO_SETTINGS_MODULE: 'course_discovery.settings.devstack'
 DISCOVERY_ELASTICSEARCH_HOST: 'es'
-
+COMMON_MYSQL_MIGRATE_USER: '{{ DISCOVERY_MYSQL_USER }}'
+COMMON_MYSQL_MIGRATE_PASS: '{{ DISCOVERY_MYSQL_PASSWORD }}'

playbooks/roles/discovery/templates/edx/app/discovery/devstack.sh.j2

@@ -20,7 +20,7 @@ case $COMMAND in
         {{ executable }} -c {{ discovery_home }}/discovery_gunicorn.py \
                                  {{ DISCOVERY_GUNICORN_EXTRA }} \
                                  --reload \
-                                 discovery.wsgi:application
+                                 course_discovery.wsgi:application
 
         ;;
     open)