Fix scan_build_warnings in comp_avg_pred_test.cc
Fix scan_build_warnings in comp_avg_pred_test.cc

BUG=webm:1575

Change-Id: I9b5f8b08d23fd62ff6400605023f33e3890b0f2d

ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx