[tracker] functional-tests: Fix use of meson.build_root()

[Sam Thursfield <sthursfield src gnome org>]

commit 22062d42fbfb5a01ff175d0416aab665ebf9fe31
Author: Sam Thursfield <sam afuera me uk>
Date:   Wed May 1 11:15:33 2019 +0200

    functional-tests: Fix use of meson.build_root()
    
    We must avoid using meson.build_root() because the value changes if we
    are embedded as a subproject in another project.
    
    I discovered this issue while testing
    <https://gitlab.gnome.org/GNOME/tracker/merge_requests/74> where it
    caused GSettings schemas not to be found when Tracker wasn't installed
    into /usr . It didn't cause any problems before, because the test was
    able to fall back on the GSettings schemas from /usr.

 tests/functional-tests/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/tests/functional-tests/meson.build b/tests/functional-tests/meson.build
index e5e1d7a6b..d8d139166 100644
--- a/tests/functional-tests/meson.build
+++ b/tests/functional-tests/meson.build
@@ -37,7 +37,7 @@ dconf_profile_full_path = join_paths(meson.current_source_dir(), 'trackertest')
 
 test_env = environment()
 test_env.set('DCONF_PROFILE', dconf_profile_full_path)
-test_env.set('GSETTINGS_SCHEMA_DIR', join_paths(meson.build_root(), 'data'))
+test_env.set('GSETTINGS_SCHEMA_DIR', join_paths(build_root, 'data'))
 
 test_env.set('TRACKER_DB_ONTOLOGIES_DIR', tracker_uninstalled_nepomuk_ontologies_dir)
 test_env.set('TRACKER_FUNCTIONAL_TEST_BUILD_DIR', build_root)