Update vmware/govmomi vendor: add vapi package

Zones implementation for vSphere cloud provider needs dependencies
which are not included in current vmware/govmomi vendor. So this
update added "vapi" package to support zones.

vendor/github.com/vmware/govmomi/vim25/soap/client.go

@@ -77,6 +77,17 @@ type Client struct {
 
 var schemeMatch = regexp.MustCompile(`^\w+://`)
 
+type errInvalidCACertificate struct {
+	File string
+}
+
+func (e errInvalidCACertificate) Error() string {
+	return fmt.Sprintf(
+		"invalid certificate '%s', cannot be used as a trusted CA certificate",
+		e.File,
+	)
+}
+
 // ParseURL is wrapper around url.Parse, where Scheme defaults to "https" and Path defaults to "/sdk"
 func ParseURL(s string) (*url.URL, error) {
 	var err error
@@ -200,7 +211,11 @@ func (c *Client) SetRootCAs(file string) error {
 			return err
 		}
 
-		pool.AppendCertsFromPEM(pem)
+		if ok := pool.AppendCertsFromPEM(pem); !ok {
+			return errInvalidCACertificate{
+				File: name,
+			}
+		}
 	}
 
 	c.t.TLSClientConfig.RootCAs = pool