Don't use tar's -p with -rf, where it makes no sense.

-p only applies to tar invocations that cause extraction, but -rf is
just appending to a tar file.

toybox tar doesn't have -p, and it doesn't seem worth implementing if
this is our only "user".

Test: treehugger
Change-Id: I025c496b04cb57cb31ba81fd516fd40b158bc06b
diff --git a/tools/mktarball.sh b/tools/mktarball.sh
index ef0fe86..ced7e17 100755
--- a/tools/mktarball.sh
+++ b/tools/mktarball.sh
@@ -37,7 +37,7 @@
 #    echo "$f: dir: $is_dir curr: $curr_perms uid: $new_uid gid: $new_gid "\
 #         "perms: $new_perms"
     tar --no-recursion --numeric-owner --owner $new_uid \
-        --group $new_gid --mode $new_perms -p -rf ${target_tar} ${f}
+        --group $new_gid --mode $new_perms -rf ${target_tar} ${f}
 done
 
 if [ $? -eq 0 ] ; then