Use user specified ssh key when removing tmp key

enable_ssh_admin was not using the user specified ssh key when removing
the generated tmp key. This could result in a permission denied error.

Change-Id: I3bd4ed6c58d6bffef811ee7ebc317056b34f2d3c
Closes-Bug: #1785704

tripleoclient/workflows/deployment.py

@@ -229,7 +229,7 @@ def enable_ssh_admin(log, clients, hosts, ssh_user, ssh_key):
         for host in hosts:
             rm_tmp_key_command = ["ssh"] + ssh_options.split()
             rm_tmp_key_command += \
-                ["-l", ssh_user, host,
+                ["-i", ssh_key, "-l", ssh_user, host,
                  "sed -i -e '/%s/d' $HOME/.ssh/authorized_keys" %
                  tmp_key_comment]
             print("Removing TripleO short term key from %s" % host)