Revert upstream change that prevents pam_unix from working with sgid
shadow applications.

Authors: Steve Langasek <vorlon@debian.org>

Upstream status: to be submitted (and debated...)

--- a/modules/pam_unix/passverify.c
+++ b/modules/pam_unix/passverify.c
@@ -198,11 +198,11 @@
 			 * ...and shadow password file entry for this user,
 			 * if shadowing is enabled
 			 */
+			*spwdent = pam_modutil_getspnam(pamh, name);
 #ifndef HELPER_COMPILE
-			if (geteuid() || SELINUX_ENABLED)
+			if (*spwdent == NULL && (geteuid() || SELINUX_ENABLED))
 				return PAM_UNIX_RUN_HELPER;
 #endif
-			*spwdent = pam_modutil_getspnam(pamh, name);
 			if (*spwdent == NULL || (*spwdent)->sp_pwdp == NULL)
 				return PAM_AUTHINFO_UNAVAIL;
 		}