BUG/MINOR: compression: properly report compression stats in HTX mode

When HTX support was added to HTTP compression, a set of counters was missed,
namely comp_in and comp_byp, resulting in no stats being available for compression.

This must be backported to 1.9.
diff --git a/src/flt_http_comp.c b/src/flt_http_comp.c
index cfe864e..3c2ce36 100644
--- a/src/flt_http_comp.c
+++ b/src/flt_http_comp.c
@@ -285,9 +285,15 @@
 		flt_update_offsets(filter, msg->chn, to_forward - consumed);
 
 	if (st->comp_ctx && st->comp_ctx->cur_lvl > 0) {
+		update_freq_ctr(&global.comp_bps_in, consumed);
+		HA_ATOMIC_ADD(&strm_fe(s)->fe_counters.comp_in, consumed);
+		HA_ATOMIC_ADD(&s->be->be_counters.comp_in, consumed);
 		update_freq_ctr(&global.comp_bps_out, to_forward);
 		HA_ATOMIC_ADD(&strm_fe(s)->fe_counters.comp_out, to_forward);
 		HA_ATOMIC_ADD(&s->be->be_counters.comp_out, to_forward);
+	} else {
+		HA_ATOMIC_ADD(&strm_fe(s)->fe_counters.comp_byp, consumed);
+		HA_ATOMIC_ADD(&s->be->be_counters.comp_byp, consumed);
 	}
 	return to_forward;