btrfs: move transaction aborts to the error site in add_block_group_free_space()

[ Upstream commit b63c8c1e ]

Transaction aborts should be done next to the place the error happens,
which was not done in add_block_group_free_space().

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 1f06c942 ("btrfs: always abort transaction on failure to add block group to free space tree")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>