Duplicate requests to ROC cause display flicker

[subdavis]

Steps to reproduce

Set up page to use these sorts of options.

Click an "X" to remove one metabolite from the list.

See 2 requests in the network debugger.

They'll come back with different results, so it's a race condition for which one will load last.

[dchiquito]

This bug is also present on the OPLSDA analysis for the Group Prediction analysis.