[BZ#15003] Define MSG_FASTOPEN

[David Miller]

From: Andreas Jaeger <aj@suse.com>
Date: Fri, 11 Jan 2013 10:12:53 +0100

> 
> MSG_FASTOPEN needs to be defined as well for TCP_FASTOPEN.
> Ok to commit?

I'm OK with this, please also add it to the 2.17 branch as well
if you don't mind.