Remove ASN1_time_parse() dependency in tls_conninfo.c

Remove ASN1_time_parse() dependency in tls_conninfo.c

During r2k22 ported some of the missing OpenSSL ASN.1 time API. This is
a step towards removing the dependency of libtls on ASN1_time_parse().
The latter grew a dependency on CBS/CBB, and thus the choice is to pull
in all this code or to use a no longer maintained version of the API.
Both options are unappealing.

ok beck