Use the fast quantizer for inter mode selection

Use the fast quantizer for inter mode selection and the
regular quantizer for the rest of the encode for good quality,
speed 1.  Both performance and quality were improved.  The
quality gains will make up for the quality loss mentioned in
I9dc089007ca08129fb6c11fe7692777ebb8647b0.

Change-Id: Ia90bc9cf326a7c65d60d31fa32f6465ab6984d21