Minikube memory assets have a strange modification date

[afbjorklund]

The MemoryAsset in minikube doesn't have a date set (uses time.Time{}).

This causes errors on certain platforms, for instance on the Raspberry Pi:

pi@raspberrypi:~ $ touch -d '0001-01-01 00:00:00 +0000' /tmp/test
touch: invalid date format '0001-01-01 00:00:00 +0000'

It "works" on the regular platform, but still looks a bit odd and is probably wrong.

[afbjorklund]

The suggestion is to just skip the "touch" part, when the mtime is not set.

       scp := fmt.Sprintf("sudo test -d %s && sudo scp -t %s", f.GetTargetDir(), f.GetTargetDir())
        mtime, err := f.GetModTime()
        if err != nil {
                glog.Infof("error getting modtime for %s: %v", dst, err)
        } else {
                scp += fmt.Sprintf(" && sudo touch -d \"%s\" %s", mtime.Format(layout), dst)
        }