INT 21,3A - Remove Subdirectory (rmdir)

	AH = 3A
	DS:DX = pointer to ASCIIZ path name


	on return:
	CF = 0 if successful
	   = 1 if error
	AX = error code  (see DOS ERROR CODES)


	- allows deletion of a subdirectory as long as it exists, is empty
	  and not the current directory