[JOSM_ImageryCache]: correct database cleaning, at last

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29944 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
[JOSM_ImageryCache]: correct database cleaning, at last

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29946 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4