vp9 rtc: change PSNR thresh.
vp9 rtc: change PSNR thresh.

Change-Id: I07ccc48c76d9871ae01b56ce432f9a6661fb47b9

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