Allow use of a custom ca cert when working against S3 storages (#170)

cmd/backup/script.go

@@ -139,6 +139,7 @@ func newScript() (*script, error) {
 			RemotePath:       s.c.AwsS3Path,
 			BucketName:       s.c.AwsS3BucketName,
 			StorageClass:     s.c.AwsStorageClass,
+			CACert:           s.c.AwsEndpointCACert.Cert,
 		}
 		if s3Backend, err := s3.NewStorageBackend(s3Config, logFunc); err != nil {
 			return nil, err