g-expect-vms.adb, [...]: Fix incorrect casing of ASCII.NUL throughout.

g-expect-vms.adb, [...]: Fix incorrect casing of ASCII.NUL throughout.

2008-04-08  Thomas Quinot  <quinot@adacore.com>

	* g-expect-vms.adb, a-textio.adb, a-witeio.adb, exp_dbug.adb,
	g-expect.adb, g-locfil.adb, gnatchop.adb, gnatdll.adb, gnatlbr.adb,
	gnatmem.adb, g-regist.adb, i-vxwork.ads, mlib-utl.adb, i-vxwork-x86.ads,
	a-ztexio.adb, g-enblsp-vms-alpha.adb, g-enblsp-vms-ia64.adb,
	s-os_lib.adb, s-regpat.adb, s-regpat.ads: Fix incorrect casing of
	ASCII.NUL throughout.

From-SVN: r134008