This patch adds the ability to specify client certification and keys as
well as root certificates and revocation lists for the client as
parameters in PQconnectdb()
sslkey=fullepath_to_file
sslcert=fullpath_to_cert
ssltrustcrt=fullpath_to_trusted_cert_file
sslcrl=fullpath_to_revocation_list
Also, it fixes a but in client revocation lists that were never looking in
the application directory.