cmd/cli: fix reset DNS when doing self-uninstall

While at it, also using "ctrld uninstall" on unix platform, ensuring
everything is cleanup properly.

cmd/cli/self_kill_others.go

@@ -0,0 +1,16 @@
+//go:build !unix
+
+package cli
+
+import (
+	"os"
+
+	"github.com/rs/zerolog"
+)
+
+func selfUninstall(err error, p *prog, logger zerolog.Logger) {
+	if uninstallIfInvalidCdUID(err, p, logger) {
+		logger.Warn().Msgf("service was uninstalled because device %q does not exist", cdUID)
+		os.Exit(0)
+	}
+}