By removing the default "localhost:8080" behavior several paths in
client config began returning err == ErrEmptyConfig rather than err ==
nil. The code checking for in cluster config was wrong - the logic
should be:
1. If loading the underlying config returns a non-empty error, fail
2. If the underlying config is not equal to the default config,
return that config (it's got user input)
3. If it is possible to use in cluster config, do so
4. Otherwise return the default config (and or default EmptyConfig
error).
