webservices PR job incorrectly configured

The Jenkins job for checking webservices pull requests [1] is not properly configured. JREs (5,...) must be configured through a command line property and this causes tests to fail.

[1] https://dev-platform-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/view/Devstudio_pull_requests/job/jbosstools-webservices-Pull-Request/

Should be able to fix the job as we did for server [2].

[2] https://dev-platform-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/view/Devstudio_pull_requests/job/jbosstools-server-Pull-Request/