Set explicit value for secret token for net specs

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

README.md

@@ -164,3 +164,6 @@ running and have next data:
 1. gitlab-org/gitlab-test project.
 2. SSH key with access to the project and ID 1 that belongs to Administrator.
 3. SSH key without access to the project and ID 2.
+
+You also need to modify `secret` variable at `spec/gitlab_net_spec.rb` so tests 
+can connect to your local instance.

spec/gitlab_net_spec.rb

@@ -10,10 +10,11 @@ describe GitlabNet, vcr: true do
   let(:project) { 'gitlab-org/gitlab-test.git' }
   let(:key) { 'key-1' }
   let(:key2) { 'key-2' }
-  let(:secret) { gitlab_net.send(:secret_token) }
+  let(:secret) { "0a3938d9d95d807e94d937af3a4fbbea\n" }
 
   before do
     gitlab_net.stub(:host).and_return(host)
+    gitlab_net.stub(:secret_token).and_return(secret)
   end
 
   describe :check do