Adjustment to boost calculation in two pass.

Calculate a minimum intra value to be used in determining the
IIratio scores used in two pass, second pass.

This is to make sure sections that are low complexity" in the
intra domain are still boosted appropriately for KF/GF/ARF.

For now I have commented out the Q based adjustment of
KF boost.

Change-Id: I15deb09c5bd9b53180a2ddd3e5f575b2aba244b3

vp8/encoder/onyx_int.h

@@ -479,6 +479,8 @@ typedef struct
     double total_coded_error_left;
     double start_tot_err_left;
     double min_error;
+    double kf_intra_err_min;
+    double gf_intra_err_min;
 
     double modified_error_total;
     double modified_error_used;