Comment 1 for bug 412722

Recent bzr-svn generates revno / revid which looks like this:

In [13]: b.last_revision_info()
Out[13]: (2311, 'svn-v4:95a4280c-1b0e-0410-9f8f-80a059958c3c:trunk:3257')

So to substitute {svn} in deb_version revision:

1) check that it starts with 'svn-v4'
2) And strip rev-id to last ":" and return last digits as {svn}

I've tried to write a patch myself but I failed =(

As far as I understood it a new def is required in class BaseRecipeBranch.
I took substitute as a template basis but I don't see where get_revno_cb() is defined and where should I place alternative get_svn_revno_cb() which will return svn revision as bisected above.