[jvm-packages] add apache maven repo url and bump up default spark version to 2.0.1 (#1650)
[jvm-packages] add apache maven repo url and bump up default spark version to 2.0.1 (#1650)

* add apache maven repo url and bump up default spark version to 2.0.1

dmlc/xgboost,dmlc/xgboost,dmlc/xgboost,dmlc/xgboost,dmlc/xgboost,dmlc/xgboost