Remove support for sharded clusters using the deprecated SCCC-mode config servers. This affects sharded clusters on 3.0 or older and 3.2 in old/SCCC-mode. We cannot guarantee consistency in SCCC-mode, so this is the safest approach. Also versions 3.0 and 3.2 are very old. This resolves #233
Throw error for SCCC-mode config servers, if they exist
Update travis-ci test scripts to only expect replset-based configsvrs