issue2550715: IndexError when requesting non-existing file via http.

Reported and fixed by Cédric Krier.

Author: Bernhard Reiter

CHANGES.txt

@@ -8,6 +8,9 @@ Entries without name were done by Richard Jones.
 Features:
 Fixed:
 
+issue2550715: IndexError when requesting non-existing file via http.
+  Reported and fixed by C�dric Krier. (Bernhard)
+
 issue2550695: 'No sort or group' settings not retained when editing queries.
   Reported and fixed by John Kristensen. Tested by Satchidanand Haridas. 
   (Bernhard)

roundup/cgi/client.py

@@ -920,7 +920,10 @@ def serve_file(self, designator, dre=re.compile(r'([^\d]+)(\d+)')):
             raise Unauthorised(self._("You are not allowed to view "
                 "this file."))
 
-        mime_type = klass.get(nodeid, 'type')
+        try:
+            mime_type = klass.get(nodeid, 'type')
+        except IndexError, e:
+            raise NotFound(e)
         # Can happen for msg class:
         if not mime_type:
             mime_type = 'text/plain'