Adding a known issue for drag/drop cts tests in DR.

Drag/Drop tests built from nyc-mr1-dev won't pass
in nyc-dr1-dev because nyc-dr1-dev haven't picked up
the fix for the "drag/drop black hole" bug.

Bug: 31469490
Change-Id: I78394685cd72b9bc78ac90cb32f206fed53c1ee7
1 file changed