In VP10, REFRESH_FRAME_CONTEXT_OFF mode is only set when the error
resillient mode is on. Instead of being used to decide how to update
the frame contexts, it is used to decide if or not to reset the
frame contexts.

To verify, ran borg test on lowres set. The result is neutral.
Overall PSNR: -0.006%; SSIM: -0.006%.

Change-Id: Ic48265cf7488e80c6f5aab3eef7ba1c273506419