…) failed

In __btrfs_alloc_chunk(), if calc_per_profile_avail() failed, it will
not update the per-profile available space array.
However since device used space is already updated, this would cause a
mismatch between them.

To fix this problem, this patch will revert device used bytes when
calc_per_profile_avail() failed, and remove the newly allocated chunk.

Signed-off-by: Qu Wenruo <wqu@suse.com>