[gedit] meson: fix typo in post-install script

[Jeremy Bicha <jbicha src gnome org>]

commit 706f9101c87f3d621693c475a6b29f92997b16a3
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Sun Jan 27 08:18:19 2019 -0500

    meson: fix typo in post-install script
    
    Closes: https://gitlab.gnome.org/GNOME/gedit/issues/120

 build-aux/meson/post_install.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/build-aux/meson/post_install.py b/build-aux/meson/post_install.py
index 177f94755..15b7838bb 100755
--- a/build-aux/meson/post_install.py
+++ b/build-aux/meson/post_install.py
@@ -5,7 +5,7 @@ import subprocess
 import sys
 
 libdir = sys.argv[1]
-datadir = sys.argv[1]
+datadir = sys.argv[2]
 
 # Packaging tools define DESTDIR and this isn't needed for them
 if 'DESTDIR' not in os.environ: