Upgrade bazlets to latest stable-2.16 to build with 2.16.6 API

Change-Id: If7166c60e48b2f79f706dcda0682b4a9ad1927f6
diff --git a/WORKSPACE b/WORKSPACE
index e91d1e4..77a374e 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "b084bd74743f4303971a2a057bcea4f3352ddf4e",
+    commit = "f7986f2d3e76ae0ca12a8c43ee91205725bd95e2",
     #    local_path = "/Users/dpursehouse/git/bazlets",
 )