Fix wrong dict reference for show_network

This is actually an error that wasn't found due
to missing schema check in networks_client.

Change-Id: I131c50638e7743630a75a4140152426b89dcbed1
diff --git a/tempest/tests/services/compute/test_networks_client.py b/tempest/tests/services/compute/test_networks_client.py
index 49a2344..b47430b 100644
--- a/tempest/tests/services/compute/test_networks_client.py
+++ b/tempest/tests/services/compute/test_networks_client.py
@@ -82,7 +82,7 @@
         self.check_service_client_function(
             self.client.show_network,
             'tempest.common.service_client.ServiceClient.get',
-            {"network": self.FAKE_NETWORKS},
+            {"network": self.FAKE_NETWORK},
             bytes_body,
             network_id=self.network_id
             )