1bd69619eb
Same motivation as
7392259332
I think we should encourage removing the writable bits from
executables. This has happened to me:
https://thomask.sdf.org/blog/2019/11/09/take-care-editing-bash-scripts.html
And not having the writable bit may help prevent hardlink
corruption with OSTree in some cases.
We can't do this by default, but add a convenient treefile option
for it.
This starts out by just doing this for RPMs, but I'll add
a secondary pass which does it during postprocessing soon too.