blkid: recognize ext3 with test_fs set as ext3

It seems that if we have the test_filesystem flag set on an ext3 filesystem(!) on a system which provides ext4, blkid gets confused.

According to the current logic:

* It's not an ext4dev filesystem, because the system provides ext4.
* It's not an ext4 filesystem, because it has no ext4 features.
* It's not an ext3 filesystem, because the test flag is set.

In the end, it's nothing.

blkid should return *something* that is mountable... I'm inclined to think that ext3 should be the right answer, if no ext4-specific features are set.

This would mean just dropping the EXT2_FLAGS_TEST_FILESYS test in probe_ext3(), because ext4 & ext4dev probes have come first already.

---

Index: e2fsprogs/lib/blkid/probe.c
===================================================================
@@ -353,10 +353,6 @@ static int probe_ext3(struct blkid_probe
 	struct ext2_super_block *es;
 	es = (struct ext2_super_block *)buf;
 
-	/* Distinguish from ext4dev */
-	if (blkid_le32(es->s_flags) & EXT2_FLAGS_TEST_FILESYS)
-		return -BLKID_ERR_PARAM;

Thanks, applied.

- Ted