Remove ansible_ssh_user from Kolla configs

The option is not for Kolla to be managing, this is all on the
operator to handle the ssh communication to the other hosts.

Additionally, setting it like this will break delegate_to

Change-Id: Ib9caa7014049f87f3ece525a32f7587e33840ea9
Closes-Bug: #1496331

ansible/group_vars/all.yml

@@ -13,9 +13,6 @@ node_templates_directory: "/usr/share/kolla/templates"
 # The directory to store the config files on the destination node
 node_config_directory: "/etc/kolla"
 
-# The user Ansible uses to ssh to target nodes
-ansible_ssh_user: "kolla"
-
 
 ###################
 # Kolla options