Fix post-install script args in imageconfig being ignored (#2414)

Author: vinceaperri

toolkit/tools/imagegen/installutils/installutils.go

@@ -1842,7 +1842,7 @@ func runPostInstallScripts(installChroot *safechroot.Chroot, config configuratio
 		ReportActionf("Running post-install script: %s", path.Base(script.Path))
 		logger.Log.Infof("Running post-install script: %s", script.Path)
 		err = installChroot.UnsafeRun(func() error {
-			err := shell.ExecuteLive(squashErrors, shell.ShellProgram, "-c", scriptPath, script.Args)
+			err := shell.ExecuteLive(squashErrors, shell.ShellProgram, "-c", fmt.Sprintf("%s %s", scriptPath, script.Args))
 
 			if err != nil {
 				return err