main: fix auto-detected distro that is non-visible, tweak order

[mvo5]

This commit fixes the issue that the auto-detect distro is not visible in the progress message. It also tweaks the order of the message to show:

Building manifest for <distro>-<img-type>

to be more conistent.

Closes: #121

Note that there is a small tweak needed in the progress library, then this can be properly tested:

func TestManifestIntegrationAutodetectDistro(t *testing.T) {
	if testing.Short() {
		t.Skip("manifest generation takes a while")
	}
	if !hasDepsolveDnf() {
		t.Skip("no osbuild-depsolve-dnf binary found")
	}

	restore := main.MockNewRepoRegistry(testrepos.New)
	defer restore()

	script := `cat - > "$0".stdin`
	fakeOsbuildCmd := testutil.MockCommand(t, "osbuild", script)
	defer fakeOsbuildCmd.Restore()

	restore = main.MockDistroGetHostDistroName(func() (string, error) {
		return "centos-9", nil
	})
	defer restore()

	restore = main.MockOsArgs([]string{
		"build",
		"qcow2",
		"--arch=x86_64",
		"--progress=debug",
	})
	defer restore()

	var fakeStdout bytes.Buffer
	restore = main.MockOsStdout(&fakeStdout)
	defer restore()

	var err error
	_, stderr := testutil.CaptureStdio(t, func() {
		err = main.Run()
	})
	assert.NoError(t, err)
	assert.Contains(t, stderr, "msg: Building manifest for centos-9-qcow2")
}

[ondrejbudai]

Thanks for the quick fix!