version: fix CmdName on the tailscale-ipn.exe binary

Don't return "wg64", "wg32", etc.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

version/modinfo_test.go

@@ -5,6 +5,7 @@
 package version
 
 import (
+	"flag"
 	"os/exec"
 	"path/filepath"
 	"runtime"
@@ -36,3 +37,18 @@ func exe() string {
 	}
 	return ""
 }
+
+var findModuleInfoName = flag.String("module-info-file", "", "if non-empty, test findModuleInfo against this filename")
+
+func TestFindModuleInfoManual(t *testing.T) {
+	exe := *findModuleInfoName
+	if exe == "" {
+		t.Skip("skipping without --module-info-file filename")
+	}
+	cmd := cmdName(exe)
+	mod, err := findModuleInfo(exe)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("Got %q from: %s", cmd, mod)
+}