Disable unused Python 2 variant. am: 4b316bcda8

Original change: https://android-review.googlesource.com/c/platform/external/python/enum34/+/2221450

Change-Id: I9215c120313b34e7e3980f8622a49c111e62b1c8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>