evaluate: reject: fix dependency generation from nft -f

evaluate: reject: fix dependency generation from nft -f

When nft -f is used, ctx->cmd points to the table object, which
contains the corresponding chain, set and rule lists. The reject
statement evaluator relies on ctx->cmd->rule to add the payload
dependencies, which is doesn't point to the rule in that case.

This patch adds the rule context to the eval_ctx structure to update
the rule list of statements when generating dependencies, as the reject
statement needs.

Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=993
Reported-by: Ting-Wei Lan <lantw44@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>