Description of problem:
When updating memory limits in /etc/openshift/resource_limits.conf, the OPENSHIFT_GEAR_MEMORY_MB environment variable on applications is not updated with the new memory limits.

Version-Release number of selected component (if applicable):
2.2

How reproducible:
Always

Steps to Reproduce:
1. Create a gear and check the value of OPENSHIFT_GEAR_MEMORY_MB
2. Increase the memory limit in /etc/openshift/resource_limits.conf, following the steps at the top of the file to instantiate the changes
3. Check the value of OPENSHIFT_GEAR_MEMORY_MB again
4. Check the actual cgroup memory limit for this application at /cgroup/memory/openshift/GEAR_UUID/memory.limit_in_bytes

Actual results:
OPENSHIFT_GEAR_MEMORY_MB does not change to reflect the new memory limit

Expected results:
OPENSHIFT_GEAR_MEMORY_MB changes to reflect the new memory limit when the memory limit is changed

Additional info:
This can have a major affect on some applications, such as ruby:

https://github.com/openshift/origin-server/blob/master/cartridges/openshift-origin-cartridge-ruby/versions/shared/etc/conf.d/performance.conf.erb#L5