Add template-name as a variable that can be used in a template

In complex configurations it may be useful to have a template
print out its name so that a given job can be easily traced to
its definition.

Change-Id: I1cfed9c27a58b45ba48aeed04839bfc8f54a831e

jenkins_jobs/parser.py

@@ -294,6 +294,7 @@ class YamlParser(object):
                 if key not in params:
                     params[key] = template[key]
 
+            params['template-name'] = template_name
             expanded = deep_format(template, params, allow_empty_variables)
 
             job_name = expanded.get('name')

tests/yamlparser/fixtures/complete001.xml

@@ -104,6 +104,9 @@
     </com.sonyericsson.hudson.plugins.gerrit.trigger.hudsontrigger.GerritTrigger>
   </triggers>
   <builders>
+    <hudson.tasks.Shell>
+      <command>echo JJB template: complete001_{version}</command>
+    </hudson.tasks.Shell>
     <hudson.tasks.Shell>
       <command>#!/usr/bin/env python
 #

tests/yamlparser/fixtures/complete001.yaml

@@ -99,6 +99,7 @@
       - pre-scm-shell-ant
       - copy-files
     builders:
+      - shell: 'echo JJB template: {template-name}'
       - shell: |
          #!/usr/bin/env python
          #