btrfs: set proper message level for skinny metadata

This has been confusing people for too long, the message is really just
informative.

CC: <stable@vger.kernel.org> # 3.10+
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

fs/btrfs/disk-io.c

@@ -2509,7 +2509,7 @@ int open_ctree(struct super_block *sb,
 		features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
 
 	if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
-		printk(KERN_ERR "BTRFS: has skinny extents\n");
+		printk(KERN_INFO "BTRFS: has skinny extents\n");
 
 	/*
 	 * flag our filesystem as having big metadata blocks if