A certfile was already specified for osx but only with MacPorts,
this patch adds the certfile given with the package `openssl` with
homebrew.
You can get more info with the command `brew info openssl` on osx with
homebrew and openssl installed.
Signed-off-by: Philippe Loctaux <loctauxphilippe@gmail.com>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>