[RPC] Fix casing in getblockchaininfo to be inline with the rest of the response
[RPC] Fix casing in getblockchaininfo to be inline with the rest of the response

The response in the RPC result `starttime` is camel cased while the rest of the response seems to be lower cased.

If this was intentional please ignore this PR.

Note: case might break existing callers

Reflect the change in the test data

Change to snake case

peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin