evaluate: use existing table object from evaluation context

evaluate: use existing table object from evaluation context

Skip table object lookup if we are in the context of table declaration already,
ctx->table already points to the right table we have to use during the
evalution. Otherwise, a list corruption occurs when using the wrong table
object when it already exists in the kernel.

http://marc.info/?l=netfilter-devel&m=144179814209295&w=2

Reported-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Tested-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>