[Tracker] tracker-search-tool segfaults

["Marcus Fritzsch" <fritschy googlemail com>]

Hi.

I am currently playing with the gnome-main-menu applet, using it's
search with t-s-t. However that applet got an invalid dbus session id
(dbus restart?) and t-s-t segfaults as tracker_client is not checked
for validity.

The connect to tracker is in tracker-search-tool.c:2239 and an error
needs to be shown rather than silent exit or even segfault. There's
way to much gtk in there for me to fix it ;).

Cheers, Marcus