Don't really need extern "C" in XioMessenger.cc.

So long as the routines are static, we can avoid both the extern
blocks and forward decls.

(Suggested by Casey)

Signed-off-by: Matt Benjamin <matt@linuxbox.com>
Pull up XioPortal refactoring and bugfix.

Fixes portal vector passed to xio_bind.  Moves bind and accept
logic completely into XioPortal.

Signed-off-by: Matt Benjamin <matt@linuxbox.com>