Relax IBD check for regtest to allow mining at genesis (#3258)
Relax IBD check for regtest to allow mining at genesis (#3258)

* Relax IBD check for regtest to allow mining at genesis

* Change per review

quantumagi/StratisBitcoinFullNode,Neurosploit/StratisBitcoinFullNode,fassadlr/StratisBitcoinFullNode,Neurosploit/StratisBitcoinFullNode,bokobza/StratisBitcoinFullNode,quantumagi/StratisBitcoinFullNode,bokobza/StratisBitcoinFullNode,bokobza/StratisBitcoinFullNode,Neurosploit/StratisBitcoinFullNode,mikedennis/StratisBitcoinFullNode,mikedennis/StratisBitcoinFullNode,mikedennis/StratisBitcoinFullNode,bokobza/StratisBitcoinFullNode,mikedennis/StratisBitcoinFullNode,stratisproject/StratisBitcoinFullNode,fassadlr/StratisBitcoinFullNode,stratisproject/StratisBitcoinFullNode