postfix: upgrade from 2.11.1 to 3.0.1

1.Remove postfix-add-db6-support.patch which is not needed,
since it is backported from upstream.

2.update install.patch and makedefs.patch that context changes.

3.Install smtp-sink which listens on the named host (or address) and port.
It takes SMTP messages from the network and throws them away.
Ref: http://www.postfix.org/smtp-sink.1.html



Signed-off-by: Li Xin <lixin.fnst@cn.fujitsu.com>
Signed-off-by: Joe MacDonald <joe_macdonald@mentor.com>