Disable unused Python 2 variant. am: 5dfda218df am: 4487a904e1 am: 7b182cd345

Original change: https://android-review.googlesource.com/c/platform/external/python/cryptography/+/2221329

Change-Id: Idb720dea2f81ed7d904f3e534f598325f109113c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>