Verify gfe2_reloadable_flag_quic_disable_version_t050

We removed all remaining T050 experiments via cl/337886255 (submitted 2020-10-19), so it's now safe to deprecate that version. go/quic-versions confirms that usage has significantly dropped.

PiperOrigin-RevId: 340303300
Change-Id: Ib42fe06a0edd62b89630c3c296360e33fe2d2f87
diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index ac8de8a..ec44d48 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -37,7 +37,7 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_disable_version_q043, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_disable_version_q046, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_disable_version_q050, false)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_disable_version_t050, false)
+QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_disable_version_t050, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_disable_version_t051, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_discard_initial_packet_with_key_dropped, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_do_not_clip_received_error_code, false)