Btrfs-progs: alloc our super copy in btrfs-find-root

Dave fixed the fs_info to allocate the super copy instead of embedding it, but
he failed to notice that I open code open_ctree in btrfs-find-root so we end up
with a super that's not allocated, so we segfault whenever you try to run
btrfs-find-root.  I've fixed this up and now we don't segfault anymore.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

find-root.c

@@ -116,6 +116,7 @@ static struct btrfs_root *open_ctree_broken(int fd, const char *device)
 	}
 
 	memset(fs_info, 0, sizeof(*fs_info));
+	fs_info->super_copy = calloc(1, BTRFS_SUPER_INFO_SIZE);
 	fs_info->tree_root = tree_root;
 	fs_info->extent_root = extent_root;
 	fs_info->chunk_root = chunk_root;