Use buildnumber instead of 'build' as subdir for builders

[Try2Code]

hi!

for debugging purpose I would like to switch the default build location from being

<worker-basedir>/<buildername>/build
to
<worker-basedir>/<buildername>/<buildnumber>

This would allow to check the build files manually later.

Is this possible in the builder config? or the worker config?

The only thing I could find is the 'builddir' and 'workerbuilddir' at http://docs.buildbot.net/current/manual/configuration/builders.html
But I already use multiple workers which all have different base directories. So I don't fully understand the purpose of 'workerbuilddir' tbh.