Removed last_auto_filter_prediction_error

last_auto_filter_prediction_error is not really used.

Change-Id: Ic6e56c4076bbd250ef783ee1be46964c85f62864

vp8/encoder/onyx_int.h

@@ -343,7 +343,6 @@ typedef struct
     long long last_prediction_error;
     long long intra_error;
     long long last_intra_error;
-    long long last_auto_filter_prediction_error;
 
 #if 0
     // Experimental RD code

vp8/encoder/picklpf.c

@@ -296,7 +296,6 @@ void vp8cx_pick_filter_level(YV12_BUFFER_CONFIG *sd, VP8_COMP *cpi)
     int filt_err = 0;
     int min_filter_level;
     int max_filter_level;
-    int prediction_difference = (int)(100 * abs((int)(cpi->last_auto_filter_prediction_error - cpi->prediction_error)) / (1 + cpi->prediction_error));
 
     int filter_step;
     int filt_high = 0;
@@ -478,6 +477,5 @@ void vp8cx_pick_filter_level(YV12_BUFFER_CONFIG *sd, VP8_COMP *cpi)
     cpi->last_auto_filt_val = filt_best;
     cpi->last_auto_filt_q  = cm->base_qindex;
 
-    cpi->last_auto_filter_prediction_error = cpi->prediction_error;
     cpi->frames_since_auto_filter = 0;
 }