--stacked-on option doesn't resolve lp: urls

[Martin Pool]

bzr branch --stacked-on lp:bzr ........

eventually fails, showing that it tried to interpret lp:bzr as a relative path.

mbp@lithe% bzr push --stacked-on lp:bzr lp:~mbp/bzr/branchbuilder
Setting ssh/sftp usernames for launchpad.net.
Source format does not support stacking, using format: '1.6'
  Packs 5 (adds stacking support, requires bzr 1.6)

bzr: ERROR: Not a branch: "/home/mbp/bzr/branchbuilder/lp:bzr/".
zsh: exit 3 bzr push --stacked-on lp:bzr lp:~mbp/bzr/branchbuilder

[Jonathan Lange (jml)]

Note that it should resolve the URL to its http expansion.

[Jelmer Vernooij (jelmer)]

The issue is that in cmd_push() we call urlutils.normalize_url() on the stacked_on location, and:

charis:~/src/bzr/bzr.dev% python
Python 2.7.1+ (r271:86832, Dec 29 2010, 18:33:35)
[GCC 4.5.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from bzrlib import urlutils
>>> urlutils.normalize_url("lp:bzr")
'lp:bzrlp:bzr'