netfilter: nf_tables: do not refresh timeout when resetting element

The dump and reset command should not refresh the timeout, this command
is intended to allow users to list existing stateful objects and reset
them, element expiration should be refresh via transaction instead with
a specific command to achieve this, otherwise this is entering combo
semantics that will be hard to be undone later (eg. a user asking to
retrieve counters but _not_ requiring to refresh expiration).

Fixes: 079cd633 ("netfilter: nf_tables: Introduce NFT_MSG_GETSETELEM_RESET")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>