conformtest: Correct pwd.h expectations for XPG3.

This patch corrects some conformtest expectations for pwd.h for XPG4.

Tested for x86_64 and x86.

	* conform/data/pwd.h-data (endpwent): Do not expect for [XPG3].
	(getpwent): Likewise.
	(setpwent): Likewise.
	* conform/Makefile (test-xfail-XPG3/pwd.h/conform): Remove
	variable.