d2vm: remove non working rhel support

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

README.md

@@ -28,7 +28,11 @@ Working and tested:
 
 Need fix:
 
-- [ ] CentOS / RHEL
+- [ ] CentOS
+
+Unsupported:
+
+- [ ] RHEL
 
 The program use the `/etc/os-release` file to discover the Linux distribution and install the Kernel,
 if the file is missing, the build cannot succeed.

builder.go

@@ -333,7 +333,7 @@ func (b *builder) installKernel(ctx context.Context) error {
 		sysconfig = syslinuxCfgDebian
 	case ReleaseAlpine:
 		sysconfig = syslinuxCfgAlpine
-	case ReleaseCentOS, ReleaseRHEL:
+	case ReleaseCentOS:
 		sysconfig = syslinuxCfgCentOS
 	default:
 		return fmt.Errorf("%s: distribution not supported", b.osRelease.ID)

dockerfile.go

@@ -63,7 +63,7 @@ func NewDockerfile(release OSRelease, img, password string) (Dockerfile, error)
 		d.tmpl = ubuntuDockerfileTemplate
 	case ReleaseAlpine:
 		d.tmpl = alpineDockerfileTemplate
-	case ReleaseCentOS, ReleaseRHEL:
+	case ReleaseCentOS:
 		d.tmpl = centOSDockerfileTemplate
 	default:
 		return Dockerfile{}, fmt.Errorf("unsupported distribution: %s", release.ID)

os_release.go

@@ -46,8 +46,10 @@ func (r Release) Supported() bool {
 		return true
 	case ReleaseAlpine:
 		return true
-	case ReleaseCentOS, ReleaseRHEL:
+	case ReleaseCentOS:
 		return true
+	case ReleaseRHEL:
+		return false
 	default:
 		return false
 	}