btrfs: unfold transaction abort at __btrfs_inc_extent_ref()

Instead of having a common btrfs_abort_transaction() call for when either
insert_tree_block_ref() failed or when insert_extent_data_ref() failed,
move the btrfs_abort_transaction() to happen immediately after each one of
those calls, so that when analysing a stack trace with a transaction abort
we know which call failed.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: David Sterba <dsterba@suse.com>