display.PrintErr swallows error and app retuns with exit code 0

[jchappelow]

Most cases a command or application error should result in a non zero exit code to the shell. This does not happen when display.PrintErr is used since it swallows the error that is given back to cobra, resulting in a zero (success) exit code. This is both confusing and bad for scripting.

Another pitfall of display.PrintErr returning a nil error when given a (non-nil) error is that if misused in subfunctions rather than directly in the actually cobra RunE, it will often be used to direct logic (assuming there was no error but there was). I recently fixed several such misuses, so it would be good to somehow consider this in resolving the issue of cmd exit code.