Revert 9b95cc27c4.

We do not want to create a new setting for a on-Tower-host global
collection path at this time.

awx/settings/defaults.py

@@ -1189,9 +1189,6 @@ AWX_REQUEST_PROFILE = False
 # Delete temporary directories created to store playbook run-time
 AWX_CLEANUP_PATHS = True
 
-# Expose collections to Ansible playbooks
-AWX_ANSIBLE_COLLECTIONS_PATHS = ['/var/lib/awx/collections']
-
 MIDDLEWARE = [
     'awx.main.middleware.TimingMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',