0.12.8dev: Fix compatibility with Python < 2.6
0.12.8dev: Fix compatibility with Python < 2.6

Named tuple was added in Python 2.6. Patch by Jun Omae.

Refs #12451.


git-svn-id: 764b04d0c6fbbea0ee05220aef3208173ff13049@14718 af82e41b-90c4-0310-8c96-b1721e28e2e2

rbaumg/trac,rbaumg/trac,rbaumg/trac,rbaumg/trac