Possibly related to: JENKINS-16316

When you have a build parameter, and you try to inject a value to it, the value is not injected.

Ways to reproduce:
JOB #1 - broken
----------
1. Add build parameter called BRANCH (or whatever name you like)
2. Add shell script with

echo "BRANCH=test" > build.prop

3. Inject build.prop using the envinject plugin
4. Add shell script with

 echo ${BRANCH} 

>> this echos empty value (or the default value set to the parameter) instead of "test"

JOB #2 - Good
-----------
1. remove the parameter named BRANCH.
Rest of the steps (2-4) remain the same:
2. Add shell script with echo

"BRANCH=test" > build.prop

3. Inject build.prop using the envinject plugin
4. Add shell script with

 echo ${BRANCH} 

>> this echos "test"

Job #1 and Job #2 should both echo "test" to the screen.

This was working before we did Jenkins + plugin upgrade. (I don't remember which plugin version we had previously).

Thanks.