fix #9068 - Don't warn about empty key and empty value in upload tags



git-svn-id: http://josm.openstreetmap.de/svn/trunk@6315 0c6e7542-c601-0410-84e7-c038aed88b3b
Sonar/FindBugs - Loose coupling

git-svn-id: http://josm.openstreetmap.de/svn/trunk@6316 0c6e7542-c601-0410-84e7-c038aed88b3b