Adjust txdb locked coins balance for FINALIZE covenants

[pinheadmz]

I think we may have overlooked the impact of FINALIZE covenants on locked coins balances in the wallet. They are unusual because it is the only case where locked coins leave the wallet. Meaning someone else's locked coin balance goes up. The current txdb functions lockBalances() and unlockBalances() process covenants received into the wallet, however in this case we must also catch FINALIZE as it is being sent, since our own locked coin balance goes down (along with the total balance - name and coins get transferred)

TODO:

• Evaluate the impact of this change on exiting wallets in use. Do we need another wallet DB migration?
• Will some users have to completely restore wallet from seed and rescan like the claim-to-register issue?
• Let's make sure REVOKE and TRANSFER aren't lingering issues as well

According to my covenant statistics script, at this time there are 14 FINALIZE covenants confirmed on the blockchain, for a total value of 3,700.500000 HNS. Both the sender and receiver of these names will have inaccurate locked coin balances, that may end up throwing an assertion error depending on future wallet activity.

Similar PRs recently merged affecting txdb locked coins computation:

#438
#387
#262

[codecov-commenter]

Codecov Report

Merging #464 into master will increase coverage by 0.06%.
The diff coverage is 90.90%.

@@            Coverage Diff             @@
##           master     #464      +/-   ##
==========================================
+ Coverage   62.53%   62.59%   +0.06%     
==========================================
  Files         129      129              
  Lines       34864    34886      +22     
  Branches     5925     5935      +10     
==========================================
+ Hits        21803    21838      +35     
+ Misses      13061    13048      -13     

Impacted Files	Coverage Δ
lib/wallet/txdb.js	86.06% <90.90%> (+1.01%)	⬆️
lib/covenants/rules.js	73.04% <0.00%> (-0.15%)	⬇️
lib/covenants/namedelta.js	86.56% <0.00%> (+0.49%)	⬆️

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[pinheadmz]

@tynes great feedback thank you! All suggestions taken, pushed two more commits.

[tynes]

Maybe we could schedule a "review session" for this PR because the longer that we wait to get this in, the more difficult the upgrade will be.

[pinheadmz]

Good idea. I also think that like the change migration bug, we should evaluate and merge this fix ASAP to prevent new wallet corruption in the community, but then we need to figure out if another migration is necessary for wallets that have already been corrupted.

[coveralls]

Pull Request Test Coverage Report for Build 238000825

• 18 of 20 (90.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.8%) to 59.23%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/wallet/txdb.js	18	20	90.0%

Totals
Change from base Build 212167982:	0.8%
Covered Lines:	19387
Relevant Lines:	30471

---

💛 - Coveralls

[pinheadmz]

Ok after sitting on this for a long time, I think we should merge as is. I tried to play with a migration fix this morning but I think the best method will be a Deep Rescan and again we'll just have to explain in the CHANGELOG