Add vendoring

Signed-off-by: Justin Cormack <justin.cormack@docker.com>

vendor/github.com/docker/engine-api/client/node_remove.go

@@ -0,0 +1,10 @@
+package client
+
+import "golang.org/x/net/context"
+
+// NodeRemove removes a Node.
+func (cli *Client) NodeRemove(ctx context.Context, nodeID string) error {
+	resp, err := cli.delete(ctx, "/nodes/"+nodeID, nil, nil)
+	ensureReaderClosed(resp)
+	return err
+}