For a given IP address remove SSH keys from the known_hosts file

def remove_known_hosts(overcloud_ip):
    """For a given IP address remove SSH keys from the known_hosts file"""

    known_hosts = os.path.expanduser("~/.ssh/known_hosts")

    if os.path.exists(known_hosts):
        command = ['ssh-keygen', '-R', overcloud_ip, '-f', known_hosts]
        subprocess.check_call(command)