libtracker-common: Small changes to config file logging
tracker-preferences: Mention that TRACKER_USE_CONFIG_FILES has no effect
libtracker-common, tracker-miner-fs: Fixed config file and settings overwriting

libtracker-common: Added config tracing to avoid spaming logs most of the
time, but kept for cases where we need to see what we're doing with configs.

libtracker-common: Added +tracker_config_file_import_to_settings() We call
this now from tracker-config.c in miner-fs when using config files to update
our local GSettings. No overwriting stored GSettings happens.

tracker-miner-fs: Removed all unused _set() functions in tracker-config.[ch].

tracker-miner-fs: Only allow *local* GSettings override of verbosity and
initial-sleep from the command line.

tracker-miner-fs: Don't re-write the default config in some cases.

tracker-miner-fs: For config, don't bind DEFAULT, but only GET for most
properties, we don't want to save back what we change locally, that's what
tracker-preferences does.

https://bugzilla.gnome.org/show_bug.cgi?id=703759
Merge branch 'config-rewrite-on-start'