Build fail due to IPDB Test environment unavailable.

[alvin-reyes]

[agwego]

I rewrote 2 tests in my latest pull request that eliminates the dependency on https://test.ipdb.io and the driver will now build cleanly against my local BigchainDB instance. So if you have access to BigchainDB instance then it should be easy to update test.properties: test.api.url=https://test.ipdb.io and build cleanly.