[SPARK-10336][example] fix not being able to set intercept in LR example

`fitIntercept` is a command line option but not set in the main program.

dbtsai

Author: Shuo Xiang <sxiang@pinterest.com>

Closes #8510 from coderxiang/intercept and squashes the following commits:

57c9b7d [Shuo Xiang] fix not being able to set intercept in LR example

examples/src/main/scala/org/apache/spark/examples/ml/LogisticRegressionExample.scala

@@ -136,6 +136,7 @@ object LogisticRegressionExample {
       .setElasticNetParam(params.elasticNetParam)
       .setMaxIter(params.maxIter)
       .setTol(params.tol)
+      .setFitIntercept(params.fitIntercept)
 
     stages += lor
     val pipeline = new Pipeline().setStages(stages.toArray)