[gimp] plug-ins: fix Python plug-ins installation.

[Jehan <jehanp src gnome org>]

commit 549568918002dec4c7265b63f3c2525d1fde72cb
Author: Jehan <jehan girinstud io>
Date:   Sat Sep 14 22:39:39 2019 +0200

    plug-ins: fix Python plug-ins installation.
    
    They were installed under $libdir/gimp/2.99/ instead of
    $libdir/gimp/2.99/plug-ins/.

 plug-ins/python/meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/plug-ins/python/meson.build b/plug-ins/python/meson.build
index 302a72a8cd..f6e90e46af 100644
--- a/plug-ins/python/meson.build
+++ b/plug-ins/python/meson.build
@@ -31,7 +31,7 @@ foreach plugin : plugins
   name = plugin.get('name')
   srcs = plugin.get('srcs', name + '.py')
 
-  install_data(srcs, install_dir: gimpplugindir / name)
+  install_data(srcs, install_dir: gimpplugindir / 'plug-ins' / name)
 endforeach