Any projects which want to use Hush code from now on will need to be licensed as
GPLv3 or we will send the lawyers: https://www.softwarefreedom.org/
Notably, Komodo (KMD) is licensed as GPLv2 and is no longer compatible to receive
code changes, without causing legal issues. MIT projects, such as Zcash, also cannot pull
in changes from the Hush Full Node without permission from The Hush Developers,
which may in some circumstances grant an MIT license on a case-by-case basis.
In CreateNewBlock of miner https://github.com/KomodoPlatform/komodo/blob/master/src/miner.cpp#L331
we have a condition that prevents miners to include certain txes in
block if tx violates komodo_validate_interest check. so, if such txes
will exist in mempool and in some reason they was not miner earlier, if
they have nExpiryHeight = 0 - they NEVER will be included in block by miners.
Also, code in CTxMemPool::removeExpired that should remove such txes
from mempool didn't do it due to mistake. As a result these txes
stucks in mempool. No one can mine it, bcz no one can include it in block,
and no one get success to remove it from mempool.
Look on old code:
```
(ASSETCHAINS_SYMBOL[0] == 0
&& tipindex != 0 && komodo_validate_interest(...) ) < 0
```
But should be:
```
(ASSETCHAINS_SYMBOL[0] == 0
&& tipindex != 0 && komodo_validate_interest(...) < 0 )
```
Bcz we should compare with 0 result of komodo_validate_interest, but we
had different behaviour, due to typo.
