After doing 'git cl patch 12345' I forgot to disassociate my checkout
from  issue 12345  before uploading a new CL based on top of it.

$ git cl --version
2.0

$ git cl upload
WARNING: Change 12345 is owned by XYZ@chromium.org, but you authenticate to Gerrit as neis@chromium.org.
Uploading may fail due to lack of permissions.
Press Enter to upload, or Ctrl+C to abort

This makes sense. The issue is that pressing Ctrl+C has no effect.