[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/modern-go/concurrent/go_above_19.go b/vendor/github.com/modern-go/concurrent/go_above_19.go
new file mode 100644
index 0000000..aeabf8c
--- /dev/null
+++ b/vendor/github.com/modern-go/concurrent/go_above_19.go
@@ -0,0 +1,15 @@
+//+build go1.9
+
+package concurrent
+
+import "sync"
+
+// Map is a wrapper for sync.Map introduced in go1.9
+type Map struct {
+	sync.Map
+}
+
+// NewMap creates a thread safe Map
+func NewMap() *Map {
+	return &Map{}
+}