netfilter: nf_tables: memleak flow rule from commit path

[ Upstream commit 9dd732e0 ]

Abort path release flow rule object, however, commit path does not.
Update code to destroy these objects before releasing the transaction.

Fixes: c9626a2c

 ("netfilter: nf_tables: add hardware offload support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>