RDMap: use equal_range() instead of a for loop
RDMap: use equal_range() instead of a for loop

optimization :-)

Signed-off-by: Marek Chalupa <a05df156a69ad59faa9af9b666ef78009594c145@gmail.com>

mchalupa/dg,mchalupa/dg,mchalupa/dg,mchalupa/dg