MINOR: h3: add BUG_ON on control receive function

Add BUG_ON statement when handling a non implemented frames on the
control stream. This is required because frames must be removed from the
RX buffer or else it will stall the buffer.
diff --git a/src/h3.c b/src/h3.c
index 9be2a5b..14c56c6 100644
--- a/src/h3.c
+++ b/src/h3.c
@@ -299,14 +299,20 @@
 		/* From here, a frame must not be truncated */
 		switch (ftype) {
 		case H3_FT_CANCEL_PUSH:
+			/* XXX TODO XXX */
+			ABORT_NOW();
 			break;
 		case H3_FT_SETTINGS:
 			if (!h3_parse_settings_frm(h3, rxbuf, flen))
 				return 0;
 			break;
 		case H3_FT_GOAWAY:
+			/* XXX TODO XXX */
+			ABORT_NOW();
 			break;
 		case H3_FT_MAX_PUSH_ID:
+			/* XXX TODO XXX */
+			ABORT_NOW();
 			break;
 		default:
 			/* Error */