* src/userdel.c: Use a bool for the is_shadow_pwd, is_shadow_grp,

	* src/userdel.c: Use a bool for the is_shadow_pwd, is_shadow_grp,
	deleted_user_group, was_member, was_admin, and the
	options' flags.
	* src/userdel.c: Change path_prefix() prototype to return a bool.
	* src/userdel.c: Ignore return value of setlocale(),
	bindtextdomain(), and textdomain().
	* src/userdel.c: Ignore the return value from pam_end() since we
	are exiting anyway just afterwards.
	* src/userdel.c: Avoid implicit conversion of pointers /
	integers / chars to booleans.
	* src/userdel.c: Add brackets and parenthesis.
	* src/userdel.c: Avoid assignments in comparisons.
	* src/userdel.c: Do not ignore the return value of the *_unlock()
	functions.