Use fixed cffi wheel verison.

BUG=1233745

Change-Id: Ia94c3a2d7508875ff2c7baf46c73ffada4f1bb78
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3122638
Commit-Queue: Dirk Pranke <dpranke@google.com>
Auto-Submit: Brian Ryner <bryner@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>

gsutil.vpython

@@ -51,7 +51,7 @@ wheel: <
 
 wheel: <
   name: "infra/python/wheels/cffi/${vpython_platform}"
-  version: "version:1.14.5"
+  version: "version:1.14.5.chromium.3"
 >
 
 wheel: <