Providing the ansible_ssh_private_key_file as the private key for stack user
Providing the ansible_ssh_private_key_file as the private key for stack user

As similar to '4ff8318da20bf6589f7c74039a3b03b45e7031aa' commit, providing public key
for stack user to work with overcloud images.
Currently, playbook looks for id_rsa.pub at infrared root directory.
The change will generate the public key from the private located at the inventory hosts file.

Change-Id: Iab0fb4e20fe582a4794f6616580198bddc768cd2

redhat-openstack/infrared,okolisny/InfraRed,redhat-openstack/infrared,okolisny/InfraRed,okolisny/InfraRed,redhat-openstack/infrared