Description of problem:
When one wants to use tracked passthroughts and they are dependent on each other, result of call removeAllPassthrought is failure, because this function is getting passthroughts in order in which they were added (from getAllPassthroughts method).
This doesn't work for example with Chain and Rule, because iptables do not allow to remove chain containing rules.

For removing passthroughs I propose to go with opposite order (stack-like) to avoid these problems, if there is not other reason to go with FIFO order.

Version-Release number of selected component (if applicable):
upstream git (tested)
(but also applicable to all current versions)

How reproducible:
deterministic

Steps to Reproduce:
1. Add new chain with function addPassthrought
2. Add new rule inside this chain with function addPassthrough
3. Try to call removeAllPassthrough

Actual results:
> Error org.fedoraproject.FirewallD1.Exception: COMMAND_FAILED: '/sbin/iptables -w -t filter -X INPUT_passthrough' failed: iptables: Directory not empty.
passthroughts and iptables stays on place

Expected results:
remove passthroughts