MINOR: quic: remove received CRYPTO temporary tree storage

The previous commit switch from ncbuf to ncbmbuf as storage for received
CRYPTO frames. The latter ensures that buffering of such frames cannot
fail anymore due to gaps size.

Previously, extra mechanism were implemented on QUIC frames parsing
function to overcome the limitation of ncbuf on gaps size. Before
insertion, CRYPTO frames were stored in a temporary tree to order their
insertion. As this is not necessary anymore, this commit removes the
temporary tree insertion.

This commit is closely associated to the previous bug fix. As it
provides a neat optimization and code simplication, it can be backported
with it, but not in the next immediate release to spot potential
regression.

include/haproxy/quic_rx-t.h

@@ -58,11 +58,4 @@ struct quic_rx_packet {
 	unsigned int time_received;
 };
 
-enum quic_rx_ret_frm {
-	QUIC_RX_RET_FRM_DONE = 0, /* frame handled correctly */
-	QUIC_RX_RET_FRM_DUP,      /* frame ignored as already handled previously */
-	QUIC_RX_RET_FRM_AGAIN,    /* frame cannot be handled temporarily, caller may retry during another parsing round */
-	QUIC_RX_RET_FRM_FATAL,    /* error during frame handling, packet must not be acknowledged */
-};
-
 #endif /* _HAPROXY_RX_T_H */