Fix rc.local for systemd in nodepool-base element

Having non-shebang first line (empty one) leads to error on Xenial,
because systemd can't execute scripts without shebang, and rc.local
is not run (`status=203/EXEC`).

Change-Id: Icc2f01b89e6d582ad015009f6916379bee8af7b9

nodepool/elements/nodepool-base/finalise.d/89-unbound

@@ -37,7 +37,6 @@ chmod a+r /etc/unbound/forwarding.conf
 
 # Overwrite /etc/resolv.conf at boot
 dd of=/etc/rc.local <<EOF
-
 #!/bin/bash
 set -o xtrace