blkid: optional support for TYPE="fstype"

Adapted from patch created by T4ndeta <t4ndeta@gmail.com>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/util-linux/volume_id/luks.c b/util-linux/volume_id/luks.c
index 8ab09e3..f9b3766 100644
--- a/util-linux/volume_id/luks.c
+++ b/util-linux/volume_id/luks.c
@@ -94,7 +94,7 @@
 
 //	volume_id_set_usage(id, VOLUME_ID_CRYPTO);
 	volume_id_set_uuid(id, header->uuid, UUID_DCE_STRING);
-//	id->type = "crypto_LUKS";
+	IF_FEATURE_BLKID_TYPE(id->type = "crypto_LUKS";)
 
 	return 0;
 }