Update sonar.sh to fail if rhc port-forward fails

[jewzaam]

If you have multiple servers configured for openshift in rhc command the sonar.sh script should handle the case when you have the wrong server used for the port-forward. Right now it fails to do the port forward but the builds continue but are not able to publish. So unless you're paying attention you might not notice.

[jewzaam]

The change should be added to the sonar.sh in each individual repo as well, but I don't want to put in issues for that...

[jewzaam]

Updated title to generalize that sonar.sh should fail if port forwarding is not successful.

Other way it can fail is if you need to authenticate with rhc command.

[luan-cestari]

Made a suggestion on #20 . I think we could also evaluate the exit code returned from mvn