add pwent->pw_dir to logmessage.

inspired by Bug #557
Remove tracker miner code

tracker_miner_manager_new_full() was reported to be potentially
locking up for an unknown reason.

As we diddn't use the miner anyway for other reasons (see comment in
the code), simply #ifdef 0 the whole code.
Only run dbus-daemon if Spotlight is enabled, bug #556