It makes more sense to have the logging at the lower level so other
callers can share the goodness.
While removing so much stuff from / touching so many lines in
lxcContainerRenameAndEnableInterfaces() (which used to have this
debug/error logging), label names were changed and it was updated to
use the now-more-common method of initializing ret to -1 (failure),
then setting to 0 right before the cleanup label.
4ff9ec7dae