[SPARK-7864] [UI] Fix the logic grabbing the link from table in AllJobPage

This issue is related to #6419 .
Now AllJobPage doesn't have a "kill link" but I think fix the issue mentioned in #6419 just in case to avoid accidents in the future.

So, it's minor issue for now and I don't file this issue in JIRA.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #6432 from sarutak/remove-ambiguity-of-link and squashes the following commits:

cd1a503 [Kousuke Saruta] Fixed ambiguity link issue in AllJobPage

core/src/main/resources/org/apache/spark/ui/static/timeline-view.js

@@ -46,7 +46,7 @@ function drawApplicationTimeline(groupArray, eventObjArray, startTime) {
       };
 
       $(this).click(function() {
-        var jobPagePath = $(getSelectorForJobEntry(this)).find("a").attr("href")
+        var jobPagePath = $(getSelectorForJobEntry(this)).find("a.name-link").attr("href")
           window.location.href = jobPagePath
       });
 

core/src/main/scala/org/apache/spark/ui/jobs/AllJobsPage.scala

@@ -231,7 +231,7 @@ private[ui] class AllJobsPage(parent: JobsTab) extends WebUIPage("") {
         </td>
         <td>
           <span class="description-input" title={lastStageDescription}>{lastStageDescription}</span>
-          <a href={detailUrl}>{lastStageName}</a>
+          <a href={detailUrl} class="name-link">{lastStageName}</a>
         </td>
         <td sorttable_customkey={job.submissionTime.getOrElse(-1).toString}>
           {formattedSubmissionTime}