Solve potential race condition on known_hosts file when executing
scripts in parallel

Change-Id: I4b1eb76a79d978a9241cd08df49d9ed87e90cdc3
diff --git a/tools/test/bin/onos b/tools/test/bin/onos
index 44ba393..c74ebc6 100755
--- a/tools/test/bin/onos
+++ b/tools/test/bin/onos
@@ -34,4 +34,4 @@
 
 [ -n "$1" ] && OCI=$(find_node $1) && shift
 
-ssh -p 8101 -o StrictHostKeyChecking=no $OCI "$@"
+ssh -q -p 8101 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null $OCI "$@"
diff --git a/tools/test/bin/onos-all b/tools/test/bin/onos-all
index 6d5617d..e7d8031 100755
--- a/tools/test/bin/onos-all
+++ b/tools/test/bin/onos-all
@@ -24,5 +24,5 @@
 
 for node in $nodes; do
   echo "Issuing command on $node.."
-  ssh -p 8101 -o StrictHostKeyChecking=no $node "$@"
+  ssh -q -p 8101 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null $node "$@"
 done
diff --git a/tools/test/bin/onos-secure-ssh b/tools/test/bin/onos-secure-ssh
index cd9f12c..9bd8881 100755
--- a/tools/test/bin/onos-secure-ssh
+++ b/tools/test/bin/onos-secure-ssh
@@ -23,10 +23,6 @@
 (umask 077; touch "$HOME/.ssh/known_hosts")
 
 for node in $nodes; do
-    # Prune the node entry from the known hosts file since server key changes
-    ssh-keygen -f "$HOME/.ssh/known_hosts" -R [$node]:8101 ||
-        ( echo "Failed to remove key from known_hosts" >&2 && exit 1 )
-
     # Setup passwordless login for the local user on the remote node
     ssh $ONOS_USER@$node "
         [ ! -f ~/.ssh/id_rsa.pub ] && ssh-keygen -t rsa -f ~/.ssh/id_rsa -P '' -q