[gnome-build-meta] Pass -Dgtk_doc=false to meson modules, not -Ddisable_gtkdoc=true

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 47a95e0063eec95b4ed2030fc69c463d22a6a9b9
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Sat Mar 3 17:57:07 2018 -0600

    Pass -Dgtk_doc=false to meson modules, not -Ddisable_gtkdoc=true
    
    -Ddisable_gtkdoc=true is something I made up myself that few modules
    actually started using. -Dgtk_doc=false has become our de-facto standard
    flag for this.

 project.conf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/project.conf b/project.conf
index 4f898bd..6fa0108 100644
--- a/project.conf
+++ b/project.conf
@@ -84,7 +84,7 @@ elements:
       python-install: '%{python} setup.py install --root "%{install-root}"'
   meson:
     variables:
-      meson-extra: --buildtype=debugoptimized -Ddisable_gtkdoc=true
+      meson-extra: --buildtype=debugoptimized -Dgtk_doc=false
 
 # Define some behavior for `bst shell`
 #