Disable unused Python 2 variant.

Bug: 245854393
Test: presubmit
Change-Id: I555f3379d3c58a54f5dcac2d1a545ed834527cbc

Android.bp

diff --git a/Android.bp b/Android.bp
index a534f01..6c3c2bb 100644
--- a/Android.bp
+++ b/Android.bp
@@ -39,12 +39,4 @@
         "google/api_core/operations_v1/transports/*.py",
         "google/api_core/*.py",
     ],
-    version: {
-        py2: {
-            enabled: true,
-        },
-        py3: {
-            enabled: true,
-        },
-    },
 }