Follow up of PR https://github.com/tendermint/tendermint/pull/724
For https://github.com/tendermint/tendermint/issues/708
Reported initially in #708, this bug was reconfirmed
by the fuzzer.
This fix ensures that:
* if the user doesn't pass in `"id"` that we send them back
a message in an error telling them to send `"id"`. Previously
we let the handler return a 200 with nothing.
* passing in nil `params` doesn't crash
* not passing in `params` doesn't crash
* passing in non-JSON parseable data to `params` doesn't crash
Ethan Buchman
Emmanuel Odeke