f74894480 Only set fNewBlock to true in AcceptBlock when we write to disk (Matt Corallo)
fa6e49731 rpc: Avoid "duplicate" return value for invalid submitblock (MarcoFalke)
Pull request description:
This is #13395 with one more commit tacked on. MarcoFalke got tired of dealing with the stupidity of fixing a return code with too many rounds of review (not that I blame him). Honestly we should probably have no return whatsoever, but for now, this fixes it (as well as nLastBlockTime for eviction purposes). Original description: When `submitblock` of an invalid block, the return value should not be `"duplicate"`. This is only seen when the header was previously found (denoted by the incorrectly named boolean `fBlockPresent`). Fix this bug by removing `fBlockPresent`.
Backport of Core PR13439