colo-ify loses bound branch information

[Colin Watson]

<cjwatson@sarantium ~/tmp/colo-bug>$ bzr init a
Created a standalone tree (format: 2a)
<cjwatson@sarantium ~/tmp/colo-bug>$ bzr co a b
<cjwatson@sarantium ~/tmp/colo-bug>$ cd b
<cjwatson@sarantium ~/tmp/colo-bug/b>$ bzr info
Checkout (format: 2a)
Location:
       checkout root: .
  checkout of branch: /home/cjwatson/tmp/colo-bug/a
<cjwatson@sarantium ~/tmp/colo-bug/b>$ bzr colo-ify
<cjwatson@sarantium ~/tmp/colo-bug/b>$ bzr info
Lightweight checkout (format: 2a)
Location:
  light checkout root: .
   checkout of branch: .bzr/branches/trunk
    shared repository: .bzr/branches
<cjwatson@sarantium ~/tmp/colo-bug/b>$ bzr bind ../a
<cjwatson@sarantium ~/tmp/colo-bug/b>$ bzr info
Lightweight checkout (format: 2a)
Location:
       light checkout root: .
  repository checkout root: .bzr/branches/trunk
        checkout of branch: /home/cjwatson/tmp/colo-bug/a
         shared repository: .bzr/branches

The 'bzr bind' here shouldn't be necessary; 'bzr colo-ify' should restore the previous bound state.

(More commonly, of course, the bound location is remote. If you didn't remember to check what the bound location was before running 'bzr colo-ify', then it doesn't seem to be possible to recover that information afterwards.)