[bug] maxTxFee is not set to -maxtxfee if -disablewallet is also active

[junderw]

Bug Report

Current behavior:
Setting -maxtxfee=1000.00 has no effect when -disablewallet is also active.

Expected behavior
Since sendrawtransaction RPC endpoint is also affected by maxtxfee, it should take effect even when CWallet is never initialized.

Steps to reproduce:

1. Start dogecoind with -maxtxfee=1000.00 and -disablewallet
2. Use an external wallet to create a valid batch transaction with an absolute fee > 100 DOGE
3. Send it using the sendrawtransaction RPC
4. Get the absurd-high-fee error

Screenshots
None

Dogecoin Core version
v1.14.6

Machine specs

• OS: Ubuntu 20.04
• CPU: AWS vCPU (EC2)
• RAM: 8GB
• Disk size: 1000GB
• Disk Type (HD/SDD): HD

Extra information
The only place in the source that checks the -maxtxfee runtime arg is here, but at the top of the function it does an early return true if -disablewallet is active.

[patricklodder]

Thank you!

[patricklodder]

Closing this as remaining work is tracked in #3090.