Before this patch:
```
$ bitcoin-cli -testnet echo 'hello world'
error: Could not locate RPC credentials. No authentication cookie could be found, and RPC password is not set. See -rpcpassword and -stdinrpcpass. Configuration file: (/root/.bitcoin/bitcoin.conf)
```
After this patch:
```
$ bitcoin-cli -testnet echo 'hello world'
error: Could not connect to the server 127.0.0.1:18332
Make sure the bitcoind server is running and that you are connecting to the correct RPC port.
```
