Remove unused slf4jVersion pom property
Remove unused slf4jVersion pom property

jenkinsci/git-plugin,martinda/git-plugin,jenkinsci/git-plugin,MarkEWaite/git-plugin,MarkEWaite/git-plugin,martinda/git-plugin,jenkinsci/git-plugin,MarkEWaite/git-plugin,MarkEWaite/git-plugin,martinda/git-plugin,jenkinsci/git-plugin