trivial: Change name of network provided by NeutronFixture

We do this because most of our sample tests are currently using a fake
network cache due to 'stub_compute_with_ips', and that fake cache uses
the name 'private' instead of 'private-network'. When we remove that in
a future change, there's going to be a lot of refactoring. Head some of
that off by just using the same name.

Change-Id: I6339005a0d49a6dfd376523d3f9e145a00cfc3bd
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

doc/notification_samples/instance-interface_attach-end.json

@@ -11,7 +11,7 @@
                         "device_name": "tapce531f90-19",
                         "address": "192.168.1.3",
                         "version": 4,
-                        "label": "private-network",
+                        "label": "private",
                         "port_uuid": "ce531f90-199f-48c0-816c-13e38010b442",
                         "mac": "fa:16:3e:4c:2c:30",
                         "meta": {}
@@ -25,7 +25,7 @@
                         "device_name": "tap88dae9fa-0d",
                         "address": "192.168.1.30",
                         "version": 4,
-                        "label": "private-network",
+                        "label": "private",
                         "port_uuid": "88dae9fa-0dc6-49e3-8c29-3abc41e99ac9",
                         "mac": "00:0c:29:0d:11:74",
                         "meta": {}