Utility to clean known_hosts

- utility to clean known_hosts when identities of nodes defined in the cell changed

Change-Id: Iab818ca9d888cfb58c98f16f62174cc75a4f32b7
diff --git a/tools/test/bin/onos-verify-cell b/tools/test/bin/onos-verify-cell
index 7361616..8999ad4 100755
--- a/tools/test/bin/onos-verify-cell
+++ b/tools/test/bin/onos-verify-cell
@@ -7,5 +7,5 @@
 . $ONOS_ROOT/tools/build/envDefaults
 
 for node in $OCT $OCN $(env | sort | egrep "^OC[0-9]+" | cut -d= -f2); do
-    printf "%s: " $node; ssh -n -q -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o PasswordAuthentication=no $ONOS_USER@$node hostname
+    printf "%s: " $node; ssh -n -q -o StrictHostKeyChecking=no -o PasswordAuthentication=no $ONOS_USER@$node hostname
 done