This patch adds support for secure connection attempts to be cancellable. Fixes #862 Includes seastar upstream merge: * seastar f1a3520...7782ad4 (1): > Merge "rpc: Allow client connections to be cancelled" from Duarte Signed-off-by: Duarte Nunes <duarte@scylladb.com> Message-Id: <1462783335-10731-1-git-send-email-duarte@scylladb.com>