Update VERSION for 1.5.3 release

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
diff --git a/VERSION b/VERSION
index 4cda8f1..8af85be 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.5.2
+1.5.3