[gnome-desktop] configure.ac: Remove GNOME_MAINTAINER_MODE_DEFINES

[Javier Jardón Cabezas <jjardon src gnome org>]

commit 44ea32efce00f42a2d5f212745cfb4a5c5056fcc
Author: Javier Jardón <jjardon gnome org>
Date:   Sat Oct 21 00:19:42 2017 +0100

    configure.ac: Remove GNOME_MAINTAINER_MODE_DEFINES
    
    It does nothing relevant any more.
    https://wiki.gnome.org/Projects/GnomeCommon/Migration

 configure.ac |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 15cb437..9ab793e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -72,7 +72,6 @@ AC_SUBST(GNOME_DATE_COMMENT_START)
 AC_SUBST(GNOME_DATE_COMMENT_END)
 
 GNOME_COMPILE_WARNINGS([maximum])
-GNOME_MAINTAINER_MODE_DEFINES
 
 AC_ARG_ENABLE(deprecation_flags,
               [AC_HELP_STRING([--enable-deprecation-flags],