weekly release 2.8dev
MDL-45970 quiz editing: fix display of random questions.

The pass by reference meant the function was clobbering the variable in
the calling function. Once that was change, it was not strictly
necessary to rename the variable in the function, but I did anyway for
clarity.

Thanks to Rajesh Taneja for finding the problem, and identifying which
bit of code was broken. I really just made the patch.