Add chef kokoro config

Change-Id: I58054e243d8ee404e17b382f16eb1bb3658847d8
diff --git a/kokoro/chef.cfg b/kokoro/chef.cfg
new file mode 100644
index 0000000..bb2bb70
--- /dev/null
+++ b/kokoro/chef.cfg
@@ -0,0 +1 @@
+build_file: "continuous-build/build/kokoro/multistrap-release.sh"