Add local-branch option

Change-Id: I5883992afc0875e2f464ff3f576b067f7d5b4ce8

jenkins_jobs/modules/scm.py

@@ -59,6 +59,7 @@ def git(self, xml_parent, data):
       when polling for changes. (if polling is enabled)
     :arg list(str) included-regions: list of file/folders to include
     :arg list(str) excluded-regions: list of file/folders to exclude
+    :arg str local-branch: Checkout/merge to local branch
     :arg dict merge:
         :merge:
             * **remote** (`string`) - name of repo that contains branch to
@@ -198,6 +199,10 @@ def git(self, xml_parent, data):
             xe.text = str(val).lower()
         else:
             xe.text = val
+
+    if 'local-branch' in data:
+        XML.SubElement(scm, 'localBranch').text = data['local-branch']
+
     browser = data.get('browser', 'auto')
     browserdict = {'githubweb': 'GithubWeb',
                    'fisheye': 'FisheyeGitRepositoryBrowser',

tests/scm/fixtures/local-branch001.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project>
+  <scm class="hudson.plugins.git.GitSCM">
+    <configVersion>2</configVersion>
+    <userRemoteConfigs>
+      <hudson.plugins.git.UserRemoteConfig>
+        <name>origin</name>
+        <refspec>+refs/heads/*:refs/remotes/origin/*</refspec>
+        <url>https://github.com/openstack-infra/jenkins-job-builder.git</url>
+      </hudson.plugins.git.UserRemoteConfig>
+    </userRemoteConfigs>
+    <branches>
+      <hudson.plugins.git.BranchSpec>
+        <name>master</name>
+      </hudson.plugins.git.BranchSpec>
+    </branches>
+    <excludedUsers/>
+    <buildChooser class="hudson.plugins.git.util.DefaultBuildChooser"/>
+    <disableSubmodules>false</disableSubmodules>
+    <recursiveSubmodules>false</recursiveSubmodules>
+    <doGenerateSubmoduleConfigurations>false</doGenerateSubmoduleConfigurations>
+    <authorOrCommitter>false</authorOrCommitter>
+    <clean>false</clean>
+    <wipeOutWorkspace>true</wipeOutWorkspace>
+    <pruneBranches>false</pruneBranches>
+    <remotePoll>false</remotePoll>
+    <gitTool>Default</gitTool>
+    <submoduleCfg class="list"/>
+    <relativeTargetDir/>
+    <reference/>
+    <gitConfigName/>
+    <gitConfigEmail/>
+    <skipTag>false</skipTag>
+    <scmName/>
+    <useShallowClone>false</useShallowClone>
+    <localBranch>master</localBranch>
+  </scm>
+</project>

tests/scm/fixtures/local-branch001.yaml

@@ -0,0 +1,6 @@
+scm:
+  - git:
+      url: https://github.com/openstack-infra/jenkins-job-builder.git
+      branches:
+        - master
+      local-branch: master