BUG/MINOR: quic: Wrong encryption level flags checking

BUG/MINOR: quic: Wrong encryption level flags checking

This bug arrived with this commit which was supposed to fix another one:

     BUG/MINOR: quic: Wrong Application encryption level selection when probing

The aim of this patch was to prevent the Application encryption to be selected
when probing leading to ACK only packets to be sent if the ack delay timer
had fired in the meantime, leading to crashes when no 01-RTT had been sent
because the ack range tree is empty in this case.

This statement is not correct (qc->pktns->flags & QUIC_FL_PKTNS_PROBE_NEEDED)
because qc->pktns is an array of packet number space. But it is equivalent
to (qc->pktns[QUIC_TLS_PKTNS_INITIAL].flags & QUIC_FL_PKTNS_PROBE_NEEDED).

That said, the patch mentionned above is not more useful since this following
which disable the ack time during the handshakes:

    BUG/MINOR: quic: Do not use ack delay during the handshakes

This commit revert the first patch mentionned above.

Must be backported as far as 2.6.