[Dovecot] 2.0.alpha3 typo patch

[Mike Abbott]

--- a/src/lib-storage/mail-storage-service.c
+++ b/src/lib-storage/mail-storage-service.c
@@ -269,7 +269,7 @@
 		}
 	}
 	if (*set->mail_privileged_group != '\0') {
-		if (!parse_uid(set->mail_privileged_group, &rset.privileged_gid))
+		if (!parse_gid(set->mail_privileged_group, &rset.privileged_gid))
 			i_fatal("Unknown mail_gid group: %s", set->mail_gid);
 	}
 	if (*set->mail_access_groups != '\0')