[RFC] commit --fixes xxx: please, store actual bug id in addition to full URL

[Alexander Belchenko]

It's not quite rfc, just as the question I'd like to make bzr.devs aware of.

Currently bzr commit --fixes=xxx store full URL to the bug page.

In QBzr we're using special regex to extract bug id back to original 
form and then represent them in qlog view as "bug #12345".
(For example see http://qbzr.googlegroups.com/web/qlog.png)

To support every new bug tracker we have to add specialized regex
to parse full URL.

Maybe it makes more sense to store not only full URL to bug page (as 
today) but in addition and original bug id? So it will be much
easier to extract this info?