When config-download runs ceph-ansible it does so by calling
Ansible from within Ansible. This change adds a new boolean,
ceph_ansible_inherits_calling_ansible_environment (default:
true), which passes all ANSIBLE_* environment variables to
the nested Ansible execution. If a config-download user
exported a variable, e.g. ANSIBLE_PRIVATE_KEY_FILE, then
they might be surprised if they got to the Ceph installation
and it failed because Ansible was unable to SSH into the
target nodes because it didn't have that environment variable
set. Rather than require the user to know about the nested
execution and use the CephAnsibleEnvironmentVariables parameter,
assume they want the same variables passed.
Required TripleO defaults for ceph-ansible still take precedence
over config-download environment variables; ANSIBLE_ROLES_PATH
still refers to ceph-ansible roles, not config-download roles.
CephAnsibleEnvironmentVariables takes precedence over both the
calling Ansible environment variables and TripleO defaults for
ceph-ansible.
Change-Id: I428f6deb416b540dae552b5fc7a778cbc7505e8c
eca6cd03e7