Fix creating redis observer client for redis >= 0.12

Redis v0.12 and later stores the port and host of the client inside a `connectionOption` object. See https://github.com/mranney/node_redis/commit/064260d1c5f2729f413e4266c3e1e0047cfd19ad#diff-168726dbe96b3ce427e7fedce31bb0bcL1236.  This adds code to handle both new and old versions.