Debug log messages missing from output and Info messages malformed

The calls to log.Debugf() from image/baseiso.go and image/oc.go are not being output when the "image create" command is run.

4.12.0

Every time

1. Run ../bin/openshift-install agent create image --dir ./cluster-manifests/ --log-level debug

No debug log messages from log.Debugf() calls in pkg/asset/agent/image/oc.go

Debug log messages are output

Note from Zane: We should probably also use the real global logger instead of [creating a new one](https://github.com/openshift/installer/blob/2698cbb0ec7e96433a958ab6b864786c0c503c0b/pkg/asset/agent/image/baseiso.go#L109) with the default config that ignores the --log-level flag and prints weird `[0001]` stuff in the output for some reason. (The NMStateConfig manifests logging suffers from the same problem.)