[gnome-builder] build: Fix GSETTINGS_SCHEMA_DIR envvar handling in tests

[Christian Hergert <chergert src gnome org>]

commit a66b2d99f21bff6986b0dda5b7cc9ee393be934a
Author: Mart Raudsepp <leio gentoo org>
Date:   Wed Aug 29 12:30:14 2018 +0300

    build: Fix GSETTINGS_SCHEMA_DIR envvar handling in tests
    
    GSETTINGS_SCHEMA_DIR does not support multiple colon-separated paths.

 src/tests/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/tests/meson.build b/src/tests/meson.build
index 646f6f875..42c0e6d28 100644
--- a/src/tests/meson.build
+++ b/src/tests/meson.build
@@ -16,7 +16,7 @@ ide_test_env = [
   'G_TEST_BUILDDIR=@0@'.format(meson.current_build_dir()),
   'G_DEBUG=gc-friendly',
   'GSETTINGS_BACKEND=memory',
-  'GSETTINGS_SCHEMA_DIR=@0@/data/gsettings:$(GSETTINGS_SCHEMA_DIR)'.format(meson.build_root()),
+  'GSETTINGS_SCHEMA_DIR=@0@/data/gsettings'.format(meson.build_root()),
   'PYTHONDONTWRITEBYTECODE=yes',
   'MALLOC_CHECK_=2',
 #  'MALLOC_PERTURB_=$((${RANDOM:-256} % 256))',