netfilter: xt_hashlimit: Prepare for revision 2

I am planning to add a revision 2 for the hashlimit xtables module to
support higher packets per second rates. This patch renames all the
functions and variables related to revision 1 by adding _v1 at the
end of the names.

Signed-off-by: Vishwanath Pai <vpai@akamai.com>
Signed-off-by: Joshua Hunt <johunt@akamai.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>