INT 21 U - Novell NetWare - "HoldFileModeSet" (obsolete)
	AH = B7h
	AL = new value for HoldFileFlag
Return: AL = previous value of HoldFileFlag
Note:	this function provided backward compatibility with a bug in early
	  DOS versions and CP/M(Control Program for Microcomputers) An early operating system for micros based on the 8-bit Intel 8080 CPU (and later the compatible 8085 and Zilog Z80 CPUs).  MSDOS version 1.0 was essentially a clone of CP/M for the Intel 8086., but is no longer used or supported