Add missing bracket to SEGEX_IDX macro

[Matthew Dillon]

:Hi,
:
:Attached patch add missing bracket to SEGEX_IDX macro, although I
:believe we don't even use it.
:
:- Farid Kamarudin

    Fixed.  Yah, it isn't used but we'll keep it around anyway.  Thanks
    for the submission!

					-Matt