runWslCommand never returns err != nil because if there's an error, it
calls Fail (which panics, so the code after it is unreachable).
Remove error returning and checking.
Inspired by the following linter warning:
> pkg/machine/e2e/config_windows_test.go:59:56: runWslCommand - result 1 (error) is always nil (unparam)
> func runWslCommand(cmdArgs []string) (*machineSession, error) {
> ^
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
94442ae44e