Merge branch 'qa-ml-dry-retry-on-exception' into 'master'

[CE] use `retry_on_exception` instead of duplicating code

See merge request gitlab-org/gitlab-ce!29452

qa/qa/ce/strategy.rb

@@ -10,18 +10,11 @@ module QA
       end
 
       def perform_before_hooks
-        retries ||= 0
-
         # The login page could take some time to load the first time it is visited.
         # We visit the login page and wait for it to properly load only once before the tests.
+        QA::Support::Retrier.retry_on_exception do
           QA::Runtime::Browser.visit(:gitlab, QA::Page::Main::Login)
-      rescue QA::Page::Validatable::PageValidationError
-        if (retries += 1) < 3
-          Runtime::Logger.warn("The login page did not appear as expected. Retrying... (attempt ##{retries})")
-          retry
         end
-
-        raise
       end
     end
   end