This change does some minor cleanups in the
cli/command/container package;
- sort imports
- replace `fmt.Fprintf()` with `fmt.Fprintln()` if no formatting is used
- replace `fmt.Errorf()` with `errors.New()` if no formatting is used
- remove some redundant `else`'s
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
