agent,w32: Do not create a useless socket with --enable-putty-support.
* agent/agent.h (opt): Remove field ssh_support. * agent/gpg-agent.c (ssh_support): New. Replace all opt.ssh_support by this. (main): Do not set ssh_support along with setting putty_support.
- Signed-off-by: Werner Koch <wk@gnupg.org>