INT 2F - DBLSPACE.BIN - "Swap Drive" - SWAP DRIVE LETTERS OF CVF AND HOST DRIVE
	AX = 4A11h
	BX = 0002h
	DL = drive number (0=A:) of compressed drive to swap with its host
Return: AX = status (0000h,0101h,0102h,0103h) (see #02804)
Note:	this function is intended for use by DBLSPACE.EXE only
SeeAlso: AX=4A11h/BX=0000h