806b0052c3 [wallet] abort when attempting to fund a transaction above maxtxfee (Sjors Provoost)
Pull request description:
`FundTransaction` calls `GetMinimumFee` which, when the fee rate is absurdly high, quietly reduces the fee to `-maxtxfee`.
Becaue an absurdly high fee rate is usually the result of a fat finger, aborting seems safer behavior.
Before:
```
bitcoin-cli walletcreatefundedpsbt '[]' '[{"tb1q...": 0.01}]' 0 '{"feeRate": 10}' true
{
"psbt": "cHNidP8...gAA=",
"fee": 0.10000000,
"changepos": 1
}
```
After:
```
bitcoin-cli walletcreatefundedpsbt '[]' '[{"tb1q...": 0.01}]' 0 '{"feeRate": 10}' true
error code: -25
error message:
Fee exceeds maximum configured by -maxtxfee
```
QT still checks the max fee rate as expected:
<img width="566" alt="Schermafbeelding 2019-06-20 om 19 52 00" src="https://user-images.githubusercontent.com/10217/59888424-a2aa7100-9395-11e9-8ae6-8a3c1f7de585.png">
ACKs for top commit:
laanwj:
Code review ACK 806b0052c3
Tree-SHA512: bee95811711cdab100b614d2347921407af3b400aea613ca156953ed3f60b924ad29a1d335bd0e240c0b7c0fbb360226bab03294d226a5560cdf2a3f21e6d406
1212808762
