enabling bonding doesn't work

From Robert:

If you enable bonding in your site.pp, the pre-seed will fail.

--- /root/folsom-manifests/manifests/cobbler-node.pp 2013-04-25 23:57:39.728122451 -0700
+++ cobbler-node.pp 2013-04-26 00:56:44.368113611 -0700
@@ -30,7 +30,7 @@
$cobbler_node_fqdn = "${::build_node_name}.${::domain_name}"

if ($::interface_bonding == 'true'){
- $bonding = 'echo "bonding" >> /target/etc/modules ; \ '
+ $bonding = "echo 'bonding' >> /target/etc/modules ; \\"
} else {
   $bonding = ''
}

Fixes the issue, and enables bonding in the modules list as expected.