[SPARK-7522] [EXAMPLES] Removed angle brackets from dataFormat option

Applying this fix to branch 1.3, mengxr

Author: Bryan Cutler <bjcutler@us.ibm.com>

Closes #6111 from BryanCutler/dataFormat-option-1_3-7522 and squashes the following commits:

1a4c814 [Bryan Cutler] [SPARK-7522] Removed angle brackets from dataFormat option

(cherry picked from commit 9445814)
Signed-off-by: Sean Owen <sowen@cloudera.com>

examples/src/main/scala/org/apache/spark/examples/mllib/DecisionTreeRunner.scala

@@ -126,7 +126,7 @@ object DecisionTreeRunner {
         .text(s"input path to test dataset.  If given, option fracTest is ignored." +
           s" default: ${defaultParams.testInput}")
         .action((x, c) => c.copy(testInput = x))
-      opt[String]("<dataFormat>")
+      opt[String]("dataFormat")
         .text("data format: libsvm (default), dense (deprecated in Spark v1.1)")
         .action((x, c) => c.copy(dataFormat = x))
       arg[String]("<input>")

examples/src/main/scala/org/apache/spark/examples/mllib/GradientBoostedTreesRunner.scala

@@ -68,7 +68,7 @@ object GradientBoostedTreesRunner {
         .text(s"input path to test dataset.  If given, option fracTest is ignored." +
           s" default: ${defaultParams.testInput}")
         .action((x, c) => c.copy(testInput = x))
-      opt[String]("<dataFormat>")
+      opt[String]("dataFormat")
         .text("data format: libsvm (default), dense (deprecated in Spark v1.1)")
         .action((x, c) => c.copy(dataFormat = x))
       arg[String]("<input>")