Add a note about deprecated group filters

The deprecated group filters do not work if both are enabled at the
same time.  Add this in a note in the docs on the different scheduler
filters.

DocImpact
Related-bug: #1296913

Change-Id: Ic0e1b8b59c8a462e193dffb3b0f873d8aa35aa3c
Merge "Add a note about deprecated group filters"