Error message did not show filename.

The argument for the error message was "e" not the name of file to be imported.
As a result the message did not show any file name.

import_export/admin.py

@@ -225,7 +225,7 @@ def import_action(self, request, *args, **kwargs):
             except UnicodeDecodeError as e:
                 return HttpResponse(_(u"<h1>Imported file has a wrong encoding: %s</h1>" % e))
             except Exception as e:
-                return HttpResponse(_(u"<h1>%s encountred while trying to read file: %s</h1>" % (type(e).__name__, e)))
+                return HttpResponse(_(u"<h1>%s encountred while trying to read file: %s</h1>" % (type(e).__name__, import_file.name)))
             result = resource.import_data(dataset, dry_run=True,
                                           raise_errors=False,
                                           file_name=import_file.name,