A small bug fix in ext-refs on the RD mode selection
A small bug fix in ext-refs on the RD mode selection

Change-Id: I25f14fec8e806cdf98d904488aaf200169def34d

GrokImageCompression/aom,smarter/aom,mbebenita/aom,luctrudeau/aom,mbebenita/aom,GrokImageCompression/aom,GrokImageCompression/aom,mbebenita/aom,smarter/aom,luctrudeau/aom,luctrudeau/aom,smarter/aom,mbebenita/aom,mbebenita/aom,GrokImageCompression/aom,mbebenita/aom,GrokImageCompression/aom,mbebenita/aom,smarter/aom,luctrudeau/aom,mbebenita/aom,mbebenita/aom,luctrudeau/aom,luctrudeau/aom,GrokImageCompression/aom,smarter/aom,smarter/aom