MINOR: quic: Add useful error traces about qc_ssl_sess_init() failures

MINOR: quic: Add useful error traces about qc_ssl_sess_init() failures

There were no traces to diagnose qc_ssl_sess_init() failures from QUIC traces.
This patch add calls to TRACE_DEVEL() into qc_ssl_sess_init() and its caller
(qc_alloc_ssl_sock_ctx()). This was useful at least to diagnose SSL context
initialization failures when porting QUIC to the new OpenSSL 3.5 QUIC API.

Should be easily backported as far as 2.6.

(cherry picked from commit 894595b711835dba9a7432fa364ea57806b2bb0c)
Signed-off-by: Willy Tarreau <w@1wt.eu>