Verify success of parsing OpenStack cloud cacert

If no certificate is set to `OPENSTACK_CLOUD_CACERT_B64` env varaible, it
defaults to an empty string encoded. This can cause failure to connect
to OpenStack API when it uses a certificate bundle that is supplied by the
OS, instead of a private certificate. This commit fixes the issue by checking
if the certificate was parsed successfully and if not attempts to use the
host's root CA.

Author: MaysaMacedo

pkg/scope/provider.go

@@ -165,7 +165,11 @@ func NewProviderClient(cloud clientconfig.Cloud, caCert []byte, logger logr.Logg
 	}
 	if caCert != nil {
 		config.RootCAs = x509.NewCertPool()
-		config.RootCAs.AppendCertsFromPEM(caCert)
+		ok := config.RootCAs.AppendCertsFromPEM(caCert)
+		if !ok {
+			// If no certificates were successfully parsed, set RootCAs to nil to use the host's root CA
+			config.RootCAs = nil
+		}
 	}
 
 	provider.HTTPClient.Transport = &http.Transport{Proxy: http.ProxyFromEnvironment, TLSClientConfig: config}