[mutter] Bump version to 3.21.2

[Florian Müllner <fmuellner src gnome org>]

commit d7c48a854e38f9877f702d0cf51aa8bf56c8b096
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri May 27 15:15:39 2016 +0200

    Bump version to 3.21.2
    
    Update NEWS.

 NEWS         |   15 +++++++++++++++
 configure.ac |    2 +-
 2 files changed, 16 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 224b026..64e2e78 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,18 @@
+3.21.2
+======
+* Clean up surface <-> shell interaction [Jonas; #763431]
+* Fix grabbing random keys for disabled shortcuts [Rui; #766270]
+* Fix stacking of hidden windows on wayland [Rui; #764844]
+* Misc. bug fixes [Victor, Florian, Marek, Rui; #766306, #766326, #751847,
+  #763832, #766528]
+
+Contributors:
+  Jonas Ådahl, Emmanuele Bassi, Marek Chalupa, Matthias Clasen,
+  Carlos Garnacho, Rui Matos, Florian Müllner, Victor Toso
+
+Translations:
+  Tiago Santos [pt], Cédric Valmary [oc], Muhammet Kara [tr]
+
 3.21.1
 ======
 * Notify clients of pending modifier state changes [Rui; #748526]
diff --git a/configure.ac b/configure.ac
index 06f5ba5..060e5e1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@ AC_PREREQ(2.62)
 
 m4_define([mutter_major_version], [3])
 m4_define([mutter_minor_version], [21])
-m4_define([mutter_micro_version], [1])
+m4_define([mutter_micro_version], [2])
 
 m4_define([mutter_version],
           [mutter_major_version.mutter_minor_version.mutter_micro_version])