generate-tar: Add --interactive=never for rm

On generating Witherspoon PNOR tarball, rm is asking for confirmation on
removing the files in the temp dir, because the partitions are
read-only now.

Add --interactive=never so that it does not ask for interaction.

Tested: Run the script to generate Witherspoon PNOR and verify it does
        not ask for interfaction to remove the files in temp dir.

Signed-off-by: Lei YU <mine260309@gmail.com>
Change-Id: I89e94e47e02fab53eaca952a70dc672407b75cc7
diff --git a/generate-tar b/generate-tar
index 8b1c6ce..d948f33 100755
--- a/generate-tar
+++ b/generate-tar
@@ -124,7 +124,10 @@
 
 
 scratch_dir=`mktemp -d`
-trap "{ rm -r ${scratch_dir}; }" EXIT
+# Remove the temp directory on exit.
+# The files in the temp directory may contain read-only files, so add
+# --interactive=never to skip the prompt.
+trap "{ rm -r --interactive=never ${scratch_dir}; }" EXIT
 
 if [[ "${do_sign}" == true ]]; then
   if [[ -z "${private_key_path}" ]]; then