Add a gateway IP to the Management net in network_data.yaml

In several places in our documentation, we discuss enabling
the Management network as a default route in some cases.
However, we don't set this value by default. Setting a
gateway IP in the example versions of network_data.yaml
would help to demonstrate this, and would create a good
default for testing.

Change-Id: Ibbb2a403f0733a016f1f49b4acdbdcfe7b9ab5a3

network_data.yaml

@@ -106,5 +106,6 @@
   vlan: 60
   ip_subnet: '10.0.1.0/24'
   allocation_pools: [{'start': '10.0.1.4', 'end': '10.0.1.250'}]
+  gateway_ip: '10.0.1.1'
   ipv6_subnet: 'fd00:fd00:fd00:6000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:6000::10', 'end': 'fd00:fd00:fd00:6000:ffff:ffff:ffff:fffe'}]

network_data_ganesha.yaml

@@ -103,6 +103,7 @@
   vlan: 60
   ip_subnet: '10.0.1.0/24'
   allocation_pools: [{'start': '10.0.1.4', 'end': '10.0.1.250'}]
+  gateway_ip: '10.0.1.1'
   ipv6_subnet: 'fd00:fd00:fd00:6000::/64'
   ipv6_allocation_pools: [{'start': 'fd00:fd00:fd00:6000::10', 'end': 'fd00:fd00:fd00:6000:ffff:ffff:ffff:fffe'}]
 - name: StorageNFS

network_data_routed.yaml

@@ -181,4 +181,5 @@
   vlan: 60
   ip_subnet: '10.0.1.0/24'
   allocation_pools: [{'start': '10.0.1.4', 'end': '10.0.1.250'}]
+  gateway_ip: '10.0.1.1'
   ipv6_subnet: 'fd00:fd00:fd00:6000::/64'