Fix hostname property name in nats link test

We use both 'host' and 'hostname' in different places to store
the same data. This led to some mistakes in the testsuite. This
commit fixes the last mistaken use of 'host' in the NATS bosh link.

Author: Michael Mokrysz

spec/route_registar_templates_spec.rb

@@ -203,7 +203,7 @@
           name: 'nats',
           properties: {
             'nats' => {
-              'host' => 'nats-host', 'user' => 'nats-user', 'password' => 'nats-password', 'port' => 8080
+              'hostname' => 'nats-host', 'user' => 'nats-user', 'password' => 'nats-password', 'port' => 8080
             }
           },
           instances: [Bosh::Template::Test::LinkInstance.new(address: 'my-nats-address')]
@@ -214,7 +214,7 @@
     describe 'nats properties' do
       it 'renders with the default' do
         rendered_hash = JSON.parse(template.render(merged_manifest_properties, consumes: links))
-        expect(rendered_hash['message_bus_servers'][0]['host']).to eq('my-nats-address:8080')
+        expect(rendered_hash['message_bus_servers'][0]['host']).to eq('nats-host:8080')
         expect(rendered_hash['message_bus_servers'][0]['user']).to eq('nats-user')
         expect(rendered_hash['message_bus_servers'][0]['password']).to eq('nats-password')
       end
@@ -285,7 +285,7 @@
               name: 'nats',
               properties: {
                 'nats' => {
-                  'host' => '', 'user' => '', 'password' => '', 'port' => 8080
+                  'hostname' => '', 'user' => '', 'password' => '', 'port' => 8080
                 }
               }
             )
@@ -318,7 +318,7 @@
         rendered_hash = JSON.parse(template.render(merged_manifest_properties, consumes: links))
         expect(rendered_hash).to eq(
           'host' => '192.168.0.0',
-          'message_bus_servers' => [{ 'host' => 'my-nats-address:8080', 'password' => 'nats-password', 'user' => 'nats-user' }],
+          'message_bus_servers' => [{ 'host' => 'nats-host:8080', 'password' => 'nats-password', 'user' => 'nats-user' }],
           'routes' => [
             {
               'health_check' => { 'name' => 'uaa-healthcheck', 'script_path' => '/var/vcap/jobs/uaa/bin/health_check' },