[merge] allow setting debug_flags in ~/.bazaar/bazaar.conf

[Robert Collins]

Robert Collins has voted tweak.
Status is now: Conditionally approved
Comment:
I believe we have configuration option help, this new setting should be 
documented there.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3Ce01316480903052104k63c85898t88ed90dcccdc7715%40mail.gmail.com%3E
Project: Bazaar