Remove test for hardcoded ABCI version

Proposes one solution to the underlying issue behind

- informalsystems#249
- informalsystems#238
- informalsystems#233

My sense is that, if we want to set a strict abci version requirement
for the rpc client, then we should put that in the source code itself.
E.g., we might put a check on the client the abci version is within a
version range which is known to be supported. If the version is outside
that range, we could either error out or log errors/warning to alert
users that we don't guarantee compatibility.

The current approach of hardcoding in a version in the integration test
tiself seems to create a lot of busy work due to uninformative test
failures, and I'm not sure if delivers value. If the integration tests
are meant to test that the RPC client integrates correctly with ACBI,
should we really consider that integration has failed if everything
works as expected while interfacing with an older (or newer) version?

tendermint/tests/integration.rs

@@ -35,7 +35,6 @@ mod rpc {
     async fn abci_info() {
         let abci_info = localhost_rpc_client().abci_info().await.unwrap();
 
-        assert_eq!(&abci_info.version, "0.17.0");
         assert_eq!(abci_info.app_version, 1u64);
         // the kvstore app's reply will contain "{\"size\":0}" as data right from the start
         assert_eq!(&abci_info.data, "{\"size\":0}");