[release/1.3.4] params: settle the Pi vs Tau dispute

This commit increases the artificial gas floor to 4712388
(cherry picked from commit f954a8b6)

params/protocol_params.go

@@ -41,7 +41,7 @@ var (
 	Sha256WordGas          = big.NewInt(12)     //
 
 	MinGasLimit     = big.NewInt(5000)    // Minimum the gas limit may ever be.
-	GenesisGasLimit = big.NewInt(3141592) // Gas limit of the Genesis block.
+	GenesisGasLimit = big.NewInt(4712388) // Gas limit of the Genesis block.
 
 	Sha3Gas              = big.NewInt(30)     // Once per SHA3 operation.
 	Sha256Gas            = big.NewInt(60)     //