VOL-2098 Add probe argument to NewGrpcServer; Release 2.2.12

Change-Id: I76ceb9efe280c66c67edc5fef85cc8060c670a5e
diff --git a/VERSION b/VERSION
index ebbf6e5..98c938e 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.2.12-dev
+2.2.12