[josm_pdfimport] fix #josm9053 - plugin broken in r29646

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29912 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
[josm_pdfimport] fix warnings

git-svn-id: http://svn.openstreetmap.org/applications/editors/josm/plugins@29913 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4