Description of problem:
Can't thread dump rails4 quickstart of ruby-2.0 after access the app url,showing "Unable to detect application PID. Check the application's availability by accessing http://<app>-<domain>.dev.rhcloud.com."

Check the process in app, there is no Passenger RackApp process existed

It works for normal ruby-2.0 app.

Version-Release number of selected component (if applicable):
devenv_5052

How reproducible:
Always

Steps to Reproduce:
1.Create a rails application
rhc app create railsapp ruby-2.0 mysql-5.5
2.Add this upstream Rails4 quickstart repository
cd rails4
git remote add upstream -m master git://github.com/openshift/rails4-example.git
git pull -s recursive -X theirs upstream master
git push
3.Access this app
4.Threaddump this app

Actual results:
Step 4:
# rhc threaddump rails4 
 Unable to detect application PID. Check the application's availability by accessing http://rails4-abcd.dev.rhcloud.com

Expected results:
Could threaddump this app

Additional info: