Update LogStash plugin to use convert xml

- Fix doc syntax
- Add plugin="logstash" attribute

Change-Id: Ie5ea7e230d8d406bc0a597da6342a6f36e09b952
Signed-off-by: Kien Ha <kienha9922@gmail.com>

jenkins_jobs/modules/publishers.py

@@ -5253,28 +5253,31 @@ def logstash(parser, xml_parent, data):
     your job data. Also stores test metrics from Junit.
     Requires the Jenkins :jenkins-wiki:`Logstash Plugin <Logstash+Plugin>`.
 
-    :arg num max-lines: The maximum number of log lines to send to Logstash.
-        ( default 1000 )
+    :arg int max-lines: The maximum number of log lines to send to Logstash.
+        (default 1000)
     :arg bool fail-build: Mark build as failed if this step fails.
-        ( default false )
+        (default false)
 
     Minimal Example:
 
     .. literalinclude::  /../../tests/publishers/fixtures/logstash-min.yaml
+       :language: yaml
 
     Full Example:
 
     .. literalinclude::  /../../tests/publishers/fixtures/logstash-full.yaml
-
+       :language: yaml
     """
 
     logstash = XML.SubElement(xml_parent,
                               'jenkins.plugins.logstash.LogstashNotifier')
-    XML.SubElement(logstash, 'maxLines').text = str(
-        data.get('max-lines', 1000))
+    logstash.set('plugin', 'logstash')
 
-    XML.SubElement(logstash, 'failBuild').text = str(
-        data.get('fail-build', False))
+    mapping = [
+        ('max-lines', 'maxLines', 1000),
+        ('fail-build', 'failBuild', False),
+    ]
+    helpers.convert_mapping_to_xml(logstash, data, mapping, fail_required=True)
 
 
 def image_gallery(parser, xml_parent, data):

tests/publishers/fixtures/logstash-full.xml

@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <project>
   <publishers>
-    <jenkins.plugins.logstash.LogstashNotifier>
+    <jenkins.plugins.logstash.LogstashNotifier plugin="logstash">
       <maxLines>2000</maxLines>
-      <failBuild>True</failBuild>
+      <failBuild>true</failBuild>
     </jenkins.plugins.logstash.LogstashNotifier>
   </publishers>
 </project>

tests/publishers/fixtures/logstash-min.xml

@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <project>
   <publishers>
-    <jenkins.plugins.logstash.LogstashNotifier>
+    <jenkins.plugins.logstash.LogstashNotifier plugin="logstash">
       <maxLines>1000</maxLines>
-      <failBuild>False</failBuild>
+      <failBuild>false</failBuild>
     </jenkins.plugins.logstash.LogstashNotifier>
   </publishers>
 </project>