Treat a timestamp that can't be parse as if it didn't exist.

lib/osm.rb

@@ -101,8 +101,11 @@ module OSM
 
       parser.listen( :characters, %w{ time } ) do |text|
         if text && text != ''
+          begin
             date = DateTime.parse(text)
             gotdate = true
+          rescue
+          end
         end
       end