* libmisc/root_flag.c, src/gpasswd.c, src/chsh.c: Add splint

annotations.
	* src/pwconv.c, src/pwunconv.c, src/grpconv.c, src/grpunconv.c:
	Ignore return value of spw_rewind, pw_rewind, sgr_rewind, and
	gr_rewind.
	* lib/commonio.h: Both head and tail cannot be owned. Set tail as
	dependent.
	* src/expiry.c: Ignore return value of expire ().
	* src/expiry.c: The catch_signals function does not use its sig
	parameter.
	* src/userdel.c: Last audit_logger parameter is a
	shadow_audit_result, use SHADOW_AUDIT_FAILURE instead of 0.

src/grpunconv.c

@@ -188,7 +188,7 @@ int main (int argc, char **argv)
 	/*
 	 * Update group passwords if non-shadow password is "x".
 	 */
-	gr_rewind ();
+	(void) gr_rewind ();
 	while ((gr = gr_next ()) != NULL) {
 		sg = sgr_locate (gr->gr_name);
 		if (   (NULL != sg)