[MLLIB] Remove println in LogisticRegression.scala

There's no corresponding printing in linear regression. Here was my previous PR (something weird happened and I can't reopen it) https://github.com/apache/spark/pull/5272

Author: Omede Firouz <ofirouz@palantir.com>

Closes #5338 from oefirouz/println and squashes the following commits:

3f3dbf4 [Omede Firouz] [MLLIB] Remove println

mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala

@@ -180,7 +180,6 @@ class LogisticRegressionModel private[ml] (
    * The behavior of this can be adjusted using [[threshold]].
    */
   override protected def predict(features: Vector): Double = {
-    println(s"LR.predict with threshold: ${paramMap(threshold)}")
     if (score(features) > paramMap(threshold)) 1 else 0
   }