[SPARK-16385][core] Catch correct exception when calling method via reflection.

Using "Method.invoke" causes an exception to be throw, not an error, so
Utils.waitForProcess() was always throwing an exception when run on Java 7.

Author: Marcelo Vanzin

core/src/main/scala/org/apache/spark/util/Utils.scala

@@ -1813,7 +1813,7 @@ private[spark] object Utils extends Logging {
         .invoke(process, timeoutMs.asInstanceOf[java.lang.Long], TimeUnit.MILLISECONDS)
         .asInstanceOf[Boolean]
     } catch {
-      case _: NoSuchMethodError =>
+      case _: NoSuchMethodException =>
         // Otherwise implement it manually
         var terminated = false
         val startTime = System.currentTimeMillis