Add UTF-8 encoding option for console output on Jenkins

The jenkins console output characters may contain some
non-ASCII characters, like emojis.

Enforce UTF-8 encoding for the Jenkins JVM so that additional
characters can be rendered correctly.

Change-Id: I8831677ecae95662c13a40842a8e17ce193daa7d
diff --git a/jenkins-docker/master/jenkins.sh b/jenkins-docker/master/jenkins.sh
index a0d71b7..a5486f4 100755
--- a/jenkins-docker/master/jenkins.sh
+++ b/jenkins-docker/master/jenkins.sh
@@ -5,4 +5,4 @@
 
 chown -R jenkins:dockergroup /var/jenkins_home
 usermod -G docker jenkins
-gosu jenkins /usr/local/bin/run-jenkins.sh $*
+gosu jenkins bash -c "JAVA_OPTS=-Dfile.encoding=UTF-8 /usr/local/bin/run-jenkins.sh $*"