Conditionally use ruamel in get_config_file_dict() (#3257)
Conditionally use ruamel in get_config_file_dict() (#3257)

Looks like ruamel doesn't handle multiple anchors at different levels of
nesting particularly well in some cases.

Since we only really need ruamel for parsing kubernetes config files which
are generally unlikely to do similar shenanigans, we can add a flag to
only use ruamel for these (and then furthermore, only for validating CPU
overrides).
Yelp/paasta,Yelp/paasta