Disable unused Python 2 variant.

Bug: 245854393
Test: presubmit
Change-Id: I6a19142f5033f21527b1b7d55591da806209cfc0

Android.bp

diff --git a/Android.bp b/Android.bp
index 3a01311..b5de606 100644
--- a/Android.bp
+++ b/Android.bp
@@ -41,12 +41,4 @@
         "google/auth/transport/*.py",
         "google/oauth2/*.py",
     ],
-    version: {
-        py2: {
-            enabled: true,
-        },
-        py3: {
-            enabled: true,
-        },
-    },
 }