* fhandler.cc (fhandler_base::read): Remove unused signal state tweaks.

* fhandler.cc (fhandler_base::read): Remove unused signal state tweaks.
* fhandler.h (fhandler_pipe::create_selectable): Declare.
(fhandler_fifo::close_one_end): Declare.
* fhandler_fifo.cc (fhandler_fifo::close_one_end): Define.
(fhandler_fifo::open_not_mine): Use close_one_end to close appropriate end of
pipe.
* pinfo.cc (_pinfo::commune_recv): Ditto.
* pipe.cc (fhandler_pipe::create_selectable): Rename from
create_selectable_pipe.  Reorganize.
(fhandler_pipe::create): Use create_selectable.