[Tracker] Open emails with evolution

[Lorenzo Nizzi Grifi Gargiolli <cancellidimoira gmail com>]

Hi I've succefully compiled tracker from svn and everything seems to
work smoothly. One major concern is that I cannot open from t-s-t any
email (if I click on "Open" nothing happens). I'm running archlinux with
the latest stable gnome  (2.24.3).
Thanks a lot and keep up the excellent work
Lorenzo Nizzi