pgsql: Improve error reporting for SSL connection failures.

Log Message:
-----------
Improve error reporting for SSL connection failures.  Remove redundant
free operations in client_cert_cb --- openssl will also attempt to free
these structures, resulting in core dumps.

Modified Files:
--------------
    pgsql/src/backend/libpq:
        be-secure.c (r1.53 -> r1.54)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/be-secure.c.diff?r1=1.53&r2=1.54)
    pgsql/src/interfaces/libpq:
        fe-secure.c (r1.55 -> r1.56)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-secure.c.diff?r1=1.55&r2=1.56)