Revert "Store ssh_host_key of remote node"

Jobs no longer launch using this code. Revert so we can debug the
issue.

This reverts commit b6341fbe63e9043a1e76aea3f41110c373a946b7.

Change-Id: Ie8076e3e162e3f223367321d8f57ccb48a0f57f6
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
diff --git a/zuul/launcher/ansiblelaunchserver.py b/zuul/launcher/ansiblelaunchserver.py
index c70dc8b..ea0aa4e 100644
--- a/zuul/launcher/ansiblelaunchserver.py
+++ b/zuul/launcher/ansiblelaunchserver.py
@@ -1193,12 +1193,6 @@
             pre_tasks.append(dict(shell=shellargs,
                              delegate_to='127.0.0.1'))
 
-            shellargs = "ssh-keygen -E md5 -lf %s > %s" % (
-                jobdir.known_hosts,
-                os.path.join(self.ansible_root, 'ssh_host_key'))
-            pre_tasks.append(dict(shell=shellargs,
-                             delegate_to='127.0.0.1'))
-
             tasks.append(dict(block=main_block,
                               rescue=error_block))