[FIXED JENKINS-20327] When saving a list view, submit POST data with size...

[FIXED JENKINS-20327] When saving a list view, submit POST data with size proportional to the # of jobs selected for inclusion, not the number of options.
This can be done easily by setting json="true"; otherwise the default is to pass =false for each unselected job.
Ironically, even with this fix we are sending 2× what is needed,
since currently ListView.submit does not even check the json parameter for job names:
it only pays attention to top-level request parameters that the browser defines for selected checkboxes.
Ideally we could ask buildFormTree to ignore a given form element entirely, so as to avoid the wasted data.

changelog.html

@@ -55,7 +55,9 @@ Upcoming changes</a>
 <!-- Record your changes in the trunk here. -->
 <div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
 <ul class=image>
-  <li class=>
+  <li class='major bug'>
+    When Jenkins had a lot of jobs, submitting a view configuration change could overload the web server, even if few of the jobs were selected.
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-20327">issue 20327</a>)
 </ul>
 </div><!--=TRUNK-END=-->
 

core/src/main/resources/hudson/model/ListView/configure-entries.jelly

@@ -51,7 +51,7 @@ THE SOFTWARE.
           <j:set var="spanStyle" value="${it.recurse?'':'display:none'}"/>
         </j:if>
         <span class="${spanClass}" style="${spanStyle}">
-          <f:checkbox name="${job.getRelativeNameFromGroup(it.ownerItemGroup)}" checked="${it.jobNamesContains(job)}" title="${h.getRelativeDisplayNameFrom(job,it.ownerItemGroup)}" tooltip="${job.fullName}" />
+          <f:checkbox name="${job.getRelativeNameFromGroup(it.ownerItemGroup)}" checked="${it.jobNamesContains(job)}" title="${h.getRelativeDisplayNameFrom(job,it.ownerItemGroup)}" tooltip="${job.fullName}" json="true"/>
           <br/>
         </span>
       </j:forEach>