Fix typo in sample network data

The routed-networks.yaml template has a typo in it that causes it to
fail if you use it verbatim, or as the basis for your network data.

  Additional properties are not allowed (\"end'\" was unexpected)\n

This is because there is a trailing ' in the definition.

Change-Id: Ie926afdf219179ac285be96b3f05a512c970be02

network-data-samples/routed-networks.yaml

@@ -34,7 +34,7 @@
       gateway_ip: 172.16.49.1
       allocation_pools:
         - start: 172.16.49.4
-          end': 172.16.49.250
+          end: 172.16.49.250
       vlan: 40
 - name: InternalApi
   name_lower: internal_api