distro/rhel8: rename raw image in simplified installer

Rename the raw image embedded in the simplified-installer ISO to
image.raw.xz for RHEL 8.  This is the same name that's used for the raw
image when built on its own (as edge-raw-image).
The change is made for consistency with RHEL 9 and Fedora as well as for
consistency with the edge-raw-image.

internal/distro/rhel8/pipelines.go

@@ -779,7 +779,7 @@ func edgeSimplifiedInstallerPipelines(t *imageType, customizations *blueprint.Cu
 	pipelines = append(pipelines, *buildPipeline(repos, packageSetSpecs[buildPkgsKey], t.arch.distro.runner))
 	installerPackages := packageSetSpecs[installerPkgsKey]
 	kernelVer := rpmmd.GetVerStrFromPackageSpecListPanic(installerPackages, "kernel")
-	imgName := "disk.img.xz"
+	imgName := "image.raw.xz"
 	installDevice := customizations.GetInstallationDevice()
 
 	// create the raw image
@@ -813,12 +813,12 @@ func simplifiedInstallerBootISOTreePipeline(archivePipelineName, kver string, rn
 		&osbuild.CopyStageOptions{
 			Paths: []osbuild.CopyStagePath{
 				{
-					From: "input://file/disk.img.xz",
-					To:   "tree:///disk.img.xz",
+					From: "input://file/image.raw.xz",
+					To:   "tree:///image.raw.xz",
 				},
 			},
 		},
-		osbuild.NewFilesInputs(osbuild.NewFilesInputReferencesPipeline(archivePipelineName, "disk.img.xz")),
+		osbuild.NewFilesInputs(osbuild.NewFilesInputReferencesPipeline(archivePipelineName, "image.raw.xz")),
 	))
 
 	p.AddStage(osbuild.NewMkdirStage(

internal/distro/rhel8/stage_options.go

@@ -238,7 +238,7 @@ func grubISOStageOptions(installDevice, kernelVer, arch, vendor, product, osVers
 				"coreos.inst.crypt_root=1",
 				"coreos.inst.isoroot=" + isolabel,
 				"coreos.inst.install_dev=" + installDevice,
-				"coreos.inst.image_file=/run/media/iso/disk.img.xz",
+				"coreos.inst.image_file=/run/media/iso/image.raw.xz",
 				"coreos.inst.insecure"},
 		},
 		Architectures: architectures,