[VOL-2235] Mocks and interfaces for rw-core

This update consists of mocks that are used by the rw-core
during unit testing.  It also includes interfaces used for unit
tests.

Change-Id: I20ca1455c358113c3aa897acc6355e0ddbc614b7
diff --git a/vendor/github.com/prometheus/procfs/go.mod b/vendor/github.com/prometheus/procfs/go.mod
new file mode 100644
index 0000000..8a1b839
--- /dev/null
+++ b/vendor/github.com/prometheus/procfs/go.mod
@@ -0,0 +1,3 @@
+module github.com/prometheus/procfs
+
+require golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4