Updated configure.ac to 0.21.2
diff --git a/configure.ac b/configure.ac
index 39bbfbe..6d56aba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -18,7 +18,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ([2.61])
-AC_INIT([mesos], [0.21.1])
+AC_INIT([mesos], [0.21.2])
 
 # Have autoconf setup some variables related to the system.
 AC_CANONICAL_HOST