Change value to something that can be masked

The current value cannot be masked[1] but CI variables default to
masked. Rather than implementing a toggle for the masking control,
simply change the value to something that can be masked.

[1] Currently, "simple" values can be masked:
* it should be a single line
* it should not have escape characters
* it should not use variables
* it should not have any whitespace
* it should be longer than 8 characters

https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25476

qa/qa/specs/features/browser_ui/7_configure/auto_devops/create_project_with_auto_devops_spec.rb

@@ -40,7 +40,7 @@ module QA
           Resource::CiVariable.fabricate! do |resource|
             resource.project = @project
             resource.key = 'K8S_SECRET_OPTIONAL_MESSAGE'
-            resource.value = 'You can see this application secret'
+            resource.value = 'you_can_see_this_variable'
           end
 
           # Connect K8s cluster
@@ -99,7 +99,7 @@ module QA
           Page::Project::Operations::Environments::Show.perform do |show|
             show.view_deployment do
               expect(page).to have_content('Hello World!')
-              expect(page).to have_content('You can see this application secret')
+              expect(page).to have_content('you_can_see_this_variable')
             end
           end
         end