* fhandler.cc (fhandler_base::open): Drop local create_options variable.

	* fhandler.cc (fhandler_base::open): Drop local create_options variable.
	Use options member instead.
	* fhandler.h (class fhandler_base): Change type of access member to
	ACCESS_MASK.  Change get_access and set_access methods accordingly.
	Add options member.  Add get_options and set_options methods.
	(class fhandler_disk_file): Add prw_handle.
	(fhandler_disk_file::prw_open): Declare.
	(fhandler_disk_file::close): Declare.
	(fhandler_disk_file::dup): Declare.
	(fhandler_disk_file::fixup_after_fork): Declare.
	* fhandler_disk_file.cc (fhandler_disk_file::fhandler_disk_file):
	Initialize prw_handle to NULL.
	(fhandler_disk_file::close): Close prw_handle.
	(fhandler_disk_file::dup): New method.
	(fhandler_disk_file::fixup_after_fork): Set prw_handle to NULL since
	prw_handle is not inherited.
	(fhandler_disk_file::prw_open): New method.  Add long comment to
	explain current behaviour.
	(fhandler_disk_file::pread): Revert previous change.  Change to use
	prw_handle if possible.
	(fhandler_disk_file::pwrite): Change to use prw_handle if possible.