Incorrect frame used in KF boost loop.

Fixes a bug in the calculation of the boost for key frames.

Change-Id: I75e9c96a9e86379239fbbbecb56ccd529783dc7c

vp9/encoder/vp9_firstpass.c

diff --git a/vp9/encoder/vp9_firstpass.c b/vp9/encoder/vp9_firstpass.c
index a6b5ebb..e423d8d 100644
--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -2444,7 +2444,7 @@
     if ((i <= rc->max_gf_interval) ||
         ((i <= (rc->max_gf_interval * 4)) && (decay_accumulator > 0.5))) {
       const double frame_boost =
-        calc_frame_boost(cpi, this_frame, 0, KF_MAX_BOOST);
+        calc_frame_boost(cpi, &next_frame, 0, KF_MAX_BOOST);
 
       // How fast is prediction quality decaying.
       if (!detect_flash(twopass, 0)) {