Allow options to be passed to ssh

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/petitboot.exp b/petitboot.exp
index 5477054..da51dae 100644
--- a/petitboot.exp
+++ b/petitboot.exp
@@ -2,7 +2,7 @@
 
 set timeout 300
 
-spawn ssh -p2200 $argv
+spawn ssh -p2200 {*}[lrange $argv 0 end]
 
 expect {
 	-ex "Petitboot"	{ exit }