BZR_COLUMNS=0 ought to disable wrapping

[Samuel Bronson]

Instead of disabling wrapping (which is the typical use for limits of 0), setting BZR_COLUMNS=0 in the environment does something like this:

E:\home>sh -c "BZR_COLUMNS=0 bzr help commands | grep bzrtools"
bzr: ERROR: exceptions.ValueError: invalid width -1 (must be > 0)

Traceback (most recent call last):
  File "bzrlib\commands.pyo", line 912, in exception_to_return_code
  File "bzrlib\commands.pyo", line 1112, in run_bzr
  File "bzrlib\commands.pyo", line 690, in run_argv_aliases
  File "bzrlib\commands.pyo", line 705, in run
  File "bzrlib\cleanup.pyo", line 135, in run_simple
  File "bzrlib\cleanup.pyo", line 165, in _do_with_cleanups
  File "bzrlib\commands.pyo", line 1127, in ignore_pipe
  File "bzrlib\builtins.pyo", line 4246, in run
  File "bzrlib\help.pyo", line 51, in help
  File "bzrlib\help_topics\__init__.pyo", line 861, in get_help_text
  File "bzrlib\help_topics\__init__.pyo", line 90, in get_detail
  File "bzrlib\help.pyo", line 102, in _help_commands_to_text
  File "textwrap.pyo", line 346, in wrap
  File "textwrap.pyo", line 321, in wrap
  File "textwrap.pyo", line 250, in _wrap_chunks
ValueError: invalid width -1 (must be > 0)

bzr 2.2.1 on python 2.6.4 (Windows-XP-5.1.2600-SP3)
arguments: ['e:\\Tools\\Bazaar\\bzr.exe', 'help', 'commands']
encoding: 'cp1252', fsenc: 'mbcs', lang: None
plugins:
  bzrtools E:\Tools\Bazaar\plugins\bzrtools [2.2.0]
  colo E:\Tools\Bazaar\plugins\colo [0.1.0]
  explorer E:\Tools\Bazaar\plugins\explorer [1.1.0]
  fastimport E:\Tools\Bazaar\plugins\fastimport [0.9.0dev]
  launchpad E:\Tools\Bazaar\plugins\launchpad [2.2.1]
  loom E:\Tools\Bazaar\plugins\loom [2.2.1dev]
  netrc_credential_store E:\Tools\Bazaar\plugins\netrc_credential_store [2.2.1]
  news_merge E:\Tools\Bazaar\plugins\news_merge [2.2.1]
  pipeline E:\Tools\Bazaar\plugins\pipeline [unknown]
  qbzr E:\Tools\Bazaar\plugins\qbzr [0.19.2]
  rewrite E:\Tools\Bazaar\plugins\rewrite [0.6.1]
  svn E:\Tools\Bazaar\plugins\svn [1.0.4]
  upload E:\Tools\Bazaar\plugins\upload [1.0.0dev]
  xmloutput E:\Tools\Bazaar\plugins\xmloutput [0.8.6]

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
        https://bugs.launchpad.net/bzr/+filebug
    including this traceback and a description of the problem.

P.S. if there's a better way to look for a listing of commands provided by any given plugin, it might be a good idea to make it easier to find.