paths: set default state path on AIX

Updates #11361

Change-Id: I196727a540be6b7c75303f9958490b1d76189fd6
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

paths/paths_unix.go

@@ -28,6 +28,8 @@ func statePath() string {
 		return "/var/db/tailscale/tailscaled.state"
 	case "darwin":
 		return "/Library/Tailscale/tailscaled.state"
+	case "aix":
+		return "/var/tailscale/tailscaled.state"
 	default:
 		return ""
 	}