BUG/MINOR: quic: Useless use of non-contiguous buffer for in order CRYPTO data

BUG/MINOR: quic: Useless use of non-contiguous buffer for in order CRYPTO data

This issue could be reproduced with a TLS client certificate verificatio to
generate enough CRYPTO data between the client and haproxy and with dev/udp/udp-perturb
as network perturbator. Haproxy could crash thanks to a BUG_ON() call as soon as
in disorder data were bufferized into a non-contiguous buffer.

There is no need to pass a non NULL non-contiguous to qc_ssl_provide_quic_data()
from qc_ssl_provide_all_quic_data() which handles in order CRYPTO data which
have not been bufferized. If not, the first call to qc_ssl_provide_quic_data()
to process the first block of in order data leads the non-contiguous buffer
head to be advanced to a wrong offset, by <len> bytes which is the length of the
in order CRYPTO frame. This is detected by a BUG_ON() as follows:

FATAL: bug condition "ncb_ret != NCB_RET_OK" matched at src/quic_ssl.c:620
  call trace(11):
  | 0x5631cc41f3cc [0f 0b 8b 05 d4 df 48 00]: qc_ssl_provide_quic_data+0xca7/0xd78
  | 0x5631cc41f6b2 [89 45 bc 48 8b 45 b0 48]: qc_ssl_provide_all_quic_data+0x215/0x576
  | 0x5631cc3ce862 [48 8b 45 b0 8b 40 04 25]: quic_conn_io_cb+0x19a/0x8c2
  | 0x5631cc67f092 [e9 1b 02 00 00 83 45 e4]: run_tasks_from_lists+0x498/0x741
  | 0x5631cc67fb51 [89 c2 8b 45 e0 29 d0 89]: process_runnable_tasks+0x816/0x879
  | 0x5631cc625305 [8b 05 bd 0c 2d 00 83 f8]: run_poll_loop+0x8b/0x4bc
  | 0x5631cc6259c0 [48 8b 05 b9 ac 29 00 48]: main-0x2c6
  | 0x7fa6c34a2ea7 [64 48 89 04 25 30 06 00]: libpthread:+0x7ea7
  | 0x7fa6c33c2a2f [48 89 c7 b8 3c 00 00 00]: libc:clone+0x3f/0x5a

Thank you to @Tristan971 for having reported this issue in GH #2095.

No need to backport.