vp9-dynamic resize: On a resize trigger frame refresh alt_ref.

For 1 pass real-time mode. No change in behavior as only last
and golden are used as references in 1 pass real-time mode.

Change-Id: Ie4655014eee1a8b271542f29d74b2c6f7fed54c9

vp9/encoder/vp9_aq_cyclicrefresh.c

@@ -608,4 +608,5 @@ void vp9_cyclic_refresh_reset_resize(VP9_COMP *const cpi) {
   memset(cr->consec_zero_mv, 0, cm->mi_rows * cm->mi_cols);
   cr->sb_index = 0;
   cpi->refresh_golden_frame = 1;
+  cpi->refresh_alt_ref_frame = 1;
 }