Set Gerrit to 3.13.0-rc2

Change-Id: I030c44706534a3a581af9b3840c9813311d75371
diff --git a/Version.mk b/Version.mk
index e39625e..57e2b03 100644
--- a/Version.mk
+++ b/Version.mk
@@ -1,4 +1,4 @@
 VERSION=3.13.0
-WAR_VERSION=3.13.0-rc1
+WAR_VERSION=3.13.0-rc2
 BRANCH=stable-3.13
-RELEASE=0rc1
+RELEASE=0rc2