Fixes a mv pred issue introduced in a prior patch

Fixes a baseline BDRATE drop issue introduced in
0743857c1a01d40a369c89af27bb1c819253e0d9.

Partially reverts the above patch.

BUG=aomedia:544

Change-Id: Ia7cd89330cab189d22b58e183951fc6429021f42
1 file changed