rtc: Fix bug relevant to gf refresh based on Q

Frame_update_type can get modified in
av1_adjust_gf_refresh_qp_one_pass_rt() function. But, the
modified type was not considered while updating reference
frame map. Due to this reference frame map was updated
incorrectly which led to segmentation fault. This CL fixes
the issue by updating frame_update_type appropriately.

BUG=aomedia:3146

Change-Id: I5ac8e15bdb64b17a0af2a75677259312e679bc11
diff --git a/av1/encoder/encode_strategy.c b/av1/encoder/encode_strategy.c
index 683740f..d1d8283 100644
--- a/av1/encoder/encode_strategy.c
+++ b/av1/encoder/encode_strategy.c
@@ -1842,6 +1842,9 @@
   }
 #endif  // CONFIG_REALTIME_ONLY
 
+  // As the frame_update_type can get modified as part of
+  // av1_adjust_gf_refresh_qp_one_pass_rt
+  frame_update_type = get_frame_update_type(gf_group, cpi->gf_frame_index);
   if (!is_stat_generation_stage(cpi)) {
     // First pass doesn't modify reference buffer assignment or produce frame
     // flags