[gnome-tweak-tool] build: Install appstream metadata to /usr/share/metainfo/

[Jeremy Bicha <jbicha src gnome org>]

commit f1da423799b007069883d552a38e888591a0add3
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Tue Jun 6 17:41:32 2017 -0400

    build: Install appstream metadata to /usr/share/metainfo/
    
    /usr/share/appdata/ has been deprecated for a year

 meson.build |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meson.build b/meson.build
index 44f5935..5ac76a1 100644
--- a/meson.build
+++ b/meson.build
@@ -21,7 +21,7 @@ pythondir = join_paths(prefix, python3.sysconfig_path('purelib'))
 
 pkgdatadir = join_paths(datadir, meson.project_name())
 
-appdatadir = join_paths(datadir, 'appdata')
+appdatadir = join_paths(datadir, 'metainfo')
 desktopdir = join_paths(datadir, 'applications')
 gtweakdir = join_paths(pythondir, 'gtweak')
 icondir = join_paths(datadir, 'icons', 'hicolor')