small fix for `trac.mimeview.api.convert_content()`

[Shun-ichi Goto <shunichi.goto@…>]

convert_content() should returns 3 elements of tuple. Here is a patch against current svn HEAD.

trac\mimeview\api.py

@@ -304 +304 @@
         `key`, which can be either a MIME type or a key. Returns a tuple of
         (content, output_mime_type, extension)."""
         if not content:
-            return ('', 'text/plain;charset=utf-8')
+            return ('', 'text/plain;charset=utf-8', 'txt')
 
         # Ensure we have a MIME type for this content
         full_mimetype = mimetype

[Shun-ichi Goto <shunichi.goto@…>]

Fixed in r3623. See also #3581.