configure.ac: Use maintainer mode by default

See
https://mail.gnome.org/archives/desktop-devel-list/2011-September/msg00064.html

autogen.sh

@@ -17,6 +17,6 @@ PKG_NAME=mobile-broadband-provider-info
 (cd $srcdir;
     autoreconf --install --symlink &&
     autoreconf &&
-    ./configure --enable-maintainer-mode $@
+    ./configure $@
 )
 

configure.ac

@@ -2,7 +2,7 @@ AC_PREREQ(2.52)
 
 AC_INIT(mobile-broadband-provider-info, 20110511, dcbw@redhat.com, mobile-broadband-provider-info)
 AM_INIT_AUTOMAKE([-Wall -Werror foreign no-dist-gzip dist-bzip2])
-AM_MAINTAINER_MODE
+AM_MAINTAINER_MODE([enable])
 
 AC_CONFIG_FILES([
 	Makefile