[gtksourceview] autogen.sh: don't use USE_GNOME2_MACROS (deprecated)

[Sébastien Wilmet <swilmet src gnome org>]

commit 09215a95de3e0e52f8c5f330ce322e375dbba37c
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Tue Apr 28 11:01:08 2015 +0200

    autogen.sh: don't use USE_GNOME2_MACROS (deprecated)
    
    There was a warning during the build:
    
    ***Warning*** USE_GNOME2_MACROS is deprecated, you may remove it from
    autogen.sh

 autogen.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 1c1474f..1b0cd45 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -20,4 +20,4 @@ which gnome-autogen.sh || {
     exit 1
 }
 
-USE_GNOME2_MACROS=1 . gnome-autogen.sh
+. gnome-autogen.sh