Code review comment for ~smoser/cloud-init:fix/1849640-adjust-yaml-usage

OK. I just wanted to make sure that I wasn't missing something on the dump path.

For relocating; there are quite a few yaml users inside util.py so we'd still need to import
safeyaml into util; so module load wise, we're still pulling it in on any import of util. additionally, moving the load_yaml into safeyaml would mean inter-module deps; load_yaml uses decode_binary(), so we'd need to duplicate that.

I'm fine with this as it is, but would also review moving all yaml operations into safeyaml.