Make lintian-junit-report ruby 1.8 safe
Make lintian-junit-report ruby 1.8 safe

The changes from commits 7a974f4f and 21b8527d don't work when
running on Ruby 1.8:

| /usr/bin/lintian-junit-report:85:in `popen': can't convert Array into String (TypeError)
| 	from /usr/bin/lintian-junit-report:85

webtrekk-kane/jenkins-debian-glue,kartikm/jenkins-debian-glue,n054/jenkins-debian-glue,bmiklautz/jenkins-debian-glue,hashar/jenkins-debian-glue,hetznerZA/jenkins-debian-glue,n054/jenkins-debian-glue,wikimedia/operations-debs-jenkins-debian-glue,cclausen/jenkins-debian-glue,linuxmaniac/jenkins-debian-glue,vorlock/jenkins-debian-glue,wikimedia/operations-debs-jenkins-debian-glue,jbfavre/jenkins-debian-glue,vorlock/jenkins-debian-glue,mika/jenkins-debian-glue,hetznerZA/jenkins-debian-glue,webtrekk-kane/jenkins-debian-glue,tonin/jenkins-debian-glue,bmiklautz/jenkins-debian-glue,cclausen/jenkins-debian-glue,jbfavre/jenkins-debian-glue,kartikm/jenkins-debian-glue,tonin/jenkins-debian-glue,hashar/jenkins-debian-glue,zeha/jenkins-debian-glue,mika/jenkins-debian-glue,zeha/jenkins-debian-glue,linuxmaniac/jenkins-debian-glue