contrib/sslinfo needs a fix too to make hamerkop happy.

contrib/sslinfo needs a fix too to make hamerkop happy.

Re-ordering the #include's is a bit problematic here because
libpq/libpq-be.h needs to include <openssl/ssl.h>.  Instead,
let's #undef the unwanted macro after all the #includes.
This is definitely uglier than the other way, but it should
work despite possible future header rearrangements.

(A look at the openssl headers indicates that X509_NAME is the
only conflicting symbol that we use.)

In passing, remove a related but long-incorrect comment in
pg_backup_archiver.h.

Discussion: https://postgr.es/m/1051867.1635720347@sss.pgh.pa.us