We could have a file to sync with permissions rw------- but we'd create
the temp file with rw-rw-rw- minus umask, usually rw-r--r--. This
potentially exposes private data while the file is being synced.
Similarly, when ignorePerms was set and we were reusing a temp files we
would set the permissions to rw-r--r-- explicitly, potentially
overriding a strict umask that would otherwise have had the file be
rw-------.
GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3437