[gdm] configure: bump to 3.21.91

[Ray Strode <halfline src gnome org>]

commit debd44a09c065cc578771c798934a7e9d96640e2
Author: Ray Strode <rstrode redhat com>
Date:   Wed Aug 31 15:58:57 2016 -0400

    configure: bump to 3.21.91

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index e0a6696..a65127a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,7 +1,7 @@
 
 AC_PREREQ([2.60])
 AC_INIT([gdm],
-        [3.21.90],
+        [3.21.91],
         [http://bugzilla.gnome.org/enter_bug.cgi?product=gdm])
 
 AC_CONFIG_SRCDIR([daemon/gdm-manager.c])