imap-send: support Server Name Indication (RFC4366)
imap-send: support Server Name Indication (RFC4366)

To talk with some sites that serve multiple names on a single IP
address, the client needs to ask for the specific host that it wants
to talk to.

Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git