[gimp/gimp-2-8] Post-release bump version to 2.8.21

[Michael Schumacher <schumaml src gnome org>]

commit aae3b51ae43c1e2ed3a6d9d9b29ac401c48109f5
Author: Michael Schumacher <schumaml gmx de>
Date:   Wed Feb 1 09:39:28 2017 +0100

    Post-release bump version to 2.8.21

 configure.ac |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 58ce8e3..4cfd7f1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -8,11 +8,11 @@ AC_PREREQ(2.54)
 
 m4_define([gimp_major_version], [2])
 m4_define([gimp_minor_version], [8])
-m4_define([gimp_micro_version], [20])
+m4_define([gimp_micro_version], [21])
 m4_define([gimp_real_version],
           [gimp_major_version.gimp_minor_version.gimp_micro_version])
 m4_define([gimp_version], [gimp_real_version])
-m4_define([gimp_interface_age], [20])
+m4_define([gimp_interface_age], [21])
 m4_define([gimp_binary_age],
           [m4_eval(100 * gimp_minor_version + gimp_micro_version)])