[fix scala build issue] Delete whitespace in scala file (#3697)

* Delete white space in `scala/dllib/src/main/scala/com/intel/analytics/bigdl/dllib/nnframes/NNClassifier.scala` and 
`scala/dllib/src/main/scala/com/intel/analytics/bigdl/dllib/example/nnframes/xgboost/xgbClassifierTrainingExample.scala`

scala/dllib/src/main/scala/com/intel/analytics/bigdl/dllib/example/nnframes/xgboost/xgbClassifierTrainingExample.scala

@@ -32,11 +32,11 @@ object xgbClassifierTrainingExample {
     }
     val sc = NNContext.initNNContext()
     val spark = SQLContext.getOrCreate(sc)
-    
+
     val input_path = args(0) // path to iris.data
     val num_threads = args(1).toInt
     val num_round = args(2).toInt
-    val modelsave_path= args(3) // save model to this path
+    val modelsave_path = args(3) // save model to this path
 
     val schema = new StructType(Array(
       StructField("sepal length", DoubleType, true),

scala/dllib/src/main/scala/com/intel/analytics/bigdl/dllib/nnframes/NNClassifier.scala

@@ -441,7 +441,7 @@ class XGBClassifierModel private[bigdl](
   def save(path: String): Unit = {
     model.write.overwrite().save(path)
   }
-  
+
 }
 
 object XGBClassifierModel {