Configure Jenkins to find Xvfb in slave nodes

The installation path of Xvfb was not preconfigured in Jenkins. This
led to failure of build jobs, if this configuration wasn't done
manually.
This change implements adding the necessary configuration to Jenkins
at build time.

Change-Id: I877302e606aaf7e33442cd68f1d0e14fde316101
diff --git a/jenkins-docker/master/Dockerfile b/jenkins-docker/master/Dockerfile
index 56a057e..3739707 100644
--- a/jenkins-docker/master/Dockerfile
+++ b/jenkins-docker/master/Dockerfile
@@ -46,6 +46,7 @@
 COPY edit-config.xslt $JENKINS_REF
 COPY config.xml $JENKINS_REF
 COPY jenkins.plugins.logstash.LogstashInstallation.xml $JENKINS_REF
+COPY org.jenkinsci.plugins.xvfb.Xvfb.xml $JENKINS_REF
 
 RUN mkdir -p $JENKINS_REF/.ssh && \
     chown -R jenkins:jenkins $JENKINS_REF/.ssh && \
diff --git a/jenkins-docker/master/org.jenkinsci.plugins.xvfb.Xvfb.xml b/jenkins-docker/master/org.jenkinsci.plugins.xvfb.Xvfb.xml
new file mode 100644
index 0000000..20285ad
--- /dev/null
+++ b/jenkins-docker/master/org.jenkinsci.plugins.xvfb.Xvfb.xml
@@ -0,0 +1,10 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<org.jenkinsci.plugins.xvfb.Xvfb_-XvfbBuildWrapperDescriptor plugin="xvfb@1.1.3">
+  <installations>
+    <org.jenkinsci.plugins.xvfb.XvfbInstallation>
+      <name>Xvfb</name>
+      <home>/usr/bin</home>
+      <properties/>
+    </org.jenkinsci.plugins.xvfb.XvfbInstallation>
+  </installations>
+</org.jenkinsci.plugins.xvfb.Xvfb_-XvfbBuildWrapperDescriptor>
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