Adjust Ironic network sed

- due to differing netplan config format

Related-Prod: PRODX-55886
Change-Id: Ibe82c80d3d15eee146958a8b6ef676fa4d0eb73c
diff --git a/de/heat-templates/scripts/functions.sh b/de/heat-templates/scripts/functions.sh
index 4def475..fc1b4c2 100644
--- a/de/heat-templates/scripts/functions.sh
+++ b/de/heat-templates/scripts/functions.sh
@@ -748,7 +748,7 @@
 [Peer]
 Name=veth-pxe-br
 EOF
-        sed -i "s/- ${IRONIC_BAREMETAL_NETWORK_PREFIX}\([0-9]*\)/- ${IRONIC_BAREMETAL_TUNNEL_NETWORK_PREFIX}\1/" ${cloud_netplan_cfg}
+        sed -i "s/${IRONIC_BAREMETAL_NETWORK_PREFIX}\([0-9]*\)/${IRONIC_BAREMETAL_TUNNEL_NETWORK_PREFIX}\1/" ${cloud_netplan_cfg}
 cat << EOF >> ${cloud_netplan_cfg}
   vlans:
     pxe.1000: