Backout part of last change; setting PAM_USER to the invoking user

breaks things like targetpw.

auth/pam.c

@@ -82,7 +82,6 @@ pam_init(pw, promptp, auth)
     }
     if (strcmp(user_tty, "unknown"))
 	(void) pam_set_item(pamh, PAM_TTY, user_tty);
-    (void) pam_set_item(pamh, PAM_USER, user_name);
 
     auth->data = (VOID *) pamh;
     return(AUTH_SUCCESS);