Description of problem:
Given a Zend app with hot_deploy marker added, after several builds (usually two rounds of builds), the app becomes inaccessible, returnning 500 error when checking the HTTP status.

Version-Release number of selected component (if applicable):
devenv_3927

How reproducible:
always

Steps to Reproduce:
1. create a zend app
2. create a hot_deploy marker and trigger a build
3. check the availability of the app's homepage
4. make another change and trigger a second build
5. check the availability of the app again
6. repeat Step 4 and 5 several times

Actual results:
The app was accessible in Step 3, but in Step 5 its homepage became blank, returning error 500 when checking the header of the response.

Expected results:
The zend app should be always accessible after several builds with hot_deploy marker.


Additional info: