Change ifelse branches in CountVotes()

[aguycalled]

This PR fixes a bug in the logic of the CountVotes() function which can cause a proposal to morph from a Expired state back to an Accepted state when a node reindex the chainstate db and the proposal expired being accepted.

The fix involves changing the structure of some conditionals, so in the case when a proposal state and status do not match the next else if branches are not triggered. It also considers a proposal unexpired state as always expired. See the changes list for more details.

This issue is critical as it can cause two different states in different nodes and a fork in the network.

[proletesseract]

@marcus290 what have you tested on this fix? do we need to write or update any unit tests?

[proletesseract]

im compiling and testing this now

[proletesseract]

I've compiled and run the tests and they all pass. I also compiled the master branch and ran the tests against that and they pass there too. So I'm unable to say just by the tests that the bug is fixed. I am wondering if when we find a bug like this, the first step should be to write a test that fails when the bug is present but should pass when the bug is fixed. Therefore we can definitively say that the bug is fixed. I am going to see if i can modify the test to reproduce the issue on master and resolve it on the patch branch.

[marcus290]

@craigmacgregor there are two issues -

1. Reindexing will recalculate expired proposals.
2. Expired proposals will change to expired (fState: 3 under listproposals) but the status will show "accepted waiting for end of voting period". At the end of the voting cycle, the proposal will be reaccepted.

Steps to reproduce the issues:

• open testnet and let the wallet fully sync. Then reopen the wallet with -reindex-chainstate. A previously expired proposal will reappear when running listproposals because its expiry has been recalculated.
• create a short life proposal on regnet and let it expire. Then check the status upon expiry and after the next voting cycle.

I manually retested both these issues with this commit and they are fixed according to my tests.

Agreed we should write tests.