build: Require GLib 2.40, needed for g_str_match_string()

Used in tracker-stats.

https://bugzilla.gnome.org/show_bug.cgi?id=739149
Fix compilation error in case of --disable-tracker-fts
Make --disable-tracker-fts compile again
tracker-preferences: Make data reset clearer to users

https://bugzilla.gnome.org/show_bug.cgi?id=740268
Revert "Always guarantee metadata, remove --enable-guarantee-metadata option"

This reverts commit 898ac3ca17afa5d9fb382656e7e4ba4ff4b6ef39.

Conflicts:
	tests/libtracker-extract/tracker-guarantee-test.c

https://bugzilla.gnome.org/show_bug.cgi?id=733536
libtracker-extract: Fix unit tests and return value for guarantee API

- Return FALSE when we don't add to the TrackerSparqlBuilder, TRUE otherwise
- Skip any unit tests when --enable-guarantee-metadata is not configured
utils/clean-tracker-prefix: Look in 'lib64' as well as 'lib' for libraries
libtracker-extract: plug leak
tracker-fts: Make the property list per-thread data

This is global memory, and shared across threads, which doesn't play well
when (un)initializing it, as multiple simultaneous accesses can occur.
tracker-extract: Fix possible invalid memory read/write

If length is 0, out of bounds data would be read, and then written.
tracker-extract: Invert initialization order

tracker_extract_persistence_invalidate() may already be using indirectly
the priv->persistence hashtable, ensure it's set up before this is called.
tracker-extract: Don't crash if g_file_make_symbolic_link() fails with no GError

We assume error is set, but in some cases it is not. Check before using it.

https://bugzilla.gnome.org/show_bug.cgi?id=741141

https://bugzilla.redhat.com/show_bug.cgi?id=1133042
Release 1.2.5