Update to cURL 7.15.5 and integrate Scot Hetzel's patch for
really making OpenSSL support optional. Now OpenSSL and GnuTLS
are on level ground, both controlled by the OPTIONS setting.
Fortunately, it turned out that the curl_multi_socket() API change
does not affect any of the ports that use ftp/curl.
PR: 102871, 103126
Submitted by: pav, vd, Scot Hetzel <email@example.com>