tarmac depends on python-xdg but doesn't say so

On a Ubuntu system without python-xdg package installed, try to run tarmac-authenticate.
You'll get the following traceback:

Traceback (most recent call last):
  File "./tarmac-authenticate", line 19, in <module>
    from tarmac.bin import TarmacAuthenticate
  File "/home/pqm/tarmac/trunk/tarmac/bin.py", line 31, in <module>
    from tarmac.branch import Branch
  File "/home/pqm/tarmac/trunk/tarmac/branch.py", line 30, in <module>
    from tarmac.config import TarmacConfig
  File "/home/pqm/tarmac/trunk/tarmac/config.py", line 25, in <module>
    from tarmac.xdgdirs import xdg_config_home, xdg_cache_home
ImportError: cannot import name xdg_config_home

Installing python-xdg get rids of the problem.

Tarmac should say in the documentation that it depends on python-xdg or a fallback for Linux systems without python-xdg should be added to xdgdirs.py Try something like:

=== modified file 'tarmac/xdgdirs.py'
--- tarmac/xdgdirs.py 2009-07-15 03:01:14 +0000
+++ tarmac/xdgdirs.py 2009-08-18 22:56:18 +0000
@@ -28,6 +28,10 @@
         from bzrlib import win32utils as win
         xdg_config_home = win.get_appdata_location_unicode()
         xdg_cache_home = get_temp_location()
+ else:
+ home = os.environ.get('HOME')
+ xdg_config_home = os.path.join(home, '.config/')
+ xdg_cache_home = os.path.join(home, '.cache/')

 # XXX This function should be merged into bzrlib.win32utils