Sonar/Findbugs - Format string should use %n rather than \n

git-svn-id: http://josm.openstreetmap.de/svn/trunk@6334 0c6e7542-c601-0410-84e7-c038aed88b3b
Sonar/Findbugs - Unused Private Fields

git-svn-id: http://josm.openstreetmap.de/svn/trunk@6335 0c6e7542-c601-0410-84e7-c038aed88b3b