libtracker-miner: Don't fail unit tests with newer GLib on GSource API

GLib complains now if you try to remove a GSource ID that doesn't exist. The
critical means that tests can fail where before they wouldn't have.

This fixes distcheck.
tests,libtracker-fts: use a more generic test string for chinese parser tests

Instead of a made up string, which doesn't have any true meaning, and which
makes libicu and libunistring differ on the number of words found, use a simpler
sentence...

https://bugzilla.gnome.org/show_bug.cgi?id=699412
all: Switch out GSettings "schema" property for "schema-id"

Was causing unit tests to fail and made distcheck impossible
Release 0.16.5