more review updates

- use /secrets for swarm secret create route
- do not specify omitempty for secret and secret reference
- simplify lookup for secret ids
- do not use pointer for secret grpc conversion

Signed-off-by: Evan Hazlett <ejhazlett@gmail.com>

client/secret_create.go

@@ -13,7 +13,7 @@ func (cli *Client) SecretCreate(ctx context.Context, secret swarm.SecretSpec) (t
 	var headers map[string][]string
 
 	var response types.SecretCreateResponse
-	resp, err := cli.post(ctx, "/secrets/create", nil, secret, headers)
+	resp, err := cli.post(ctx, "/secrets", nil, secret, headers)
 	if err != nil {
 		return response, err
 	}