* fhandler.h (class fhandler_base): Declare new method link.

	* fhandler.h (class fhandler_base): Declare new method link.
	(class fhandler_socket): Ditto.
	(class fhandler_disk_file): Ditto.
	* fhandler.cc (fhandler_base::open): Add FILE_WRITE_ATTRIBUTES
	to query_write_control access flags.
	(fhandler_base::link): New method.
	* fhandler_disk_file.cc (fhandler_disk_file::fchmod): Don't try to
	open with O_WRONLY since query_write_control includes
	FILE_WRITE_ATTRIBUTES.
	(fhandler_disk_file::fchown): Ditto.
	(fhandler_disk_file::facl): Ditto.
	(fhandler_disk_file::link): New method.  Touch st_ctime on successful
	link.
	* fhandler_socket.cc (fhandler_socket::link): New method.
	* syscalls.cc (link): Move functionality into fhandler method link.
	Just call this method from here.