lintian-junit-report: Convert output to XML after parsing
lintian-junit-report: Convert output to XML after parsing

First thing first, original conversion creating intermediate REXML::Text
object and then converting it to string results in a more complex
wrapper around REXML::Text::normalize, which actually does the job which
is simply translating some characters to XML entities.

Although I know which characters are going to be converted
(REXML::DocType::DEFAULT_ENTITIES which is: ", &, < and >) and those
should not make difference in the parts of output being parsed it still
feels better for me to parse raw unmodified lintian output.

So instead of converting lintian output at once this change XML-escapes
string where needed. As additional bonus original lintian margins are
kept in output (previously those were squeezed).

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