Merge lp://staging/~gz/launchpadlib/trivial_homeless_launchpadlib_dir into lp://staging/launchpadlib

I need to add some tests and then I'll land this, probably next week.

For the sake of making this disappear from the +activereviews queue I'm adding a Needs Fixing as a proxy for Leonard (above) and marking it Work in Progress until there are some tests for the change.

(And by disappear I don't mean that we don't want to see this branch; if it's work in progress (which it is) it shouldn't be in the list of branches that I need to review).

Leonard no longer works for Canonical.

I've confirmed the exiting tests pass with this branch merged (it would be nice if they were easier to run), and that the change fixes the bug reported. Given the state of the launchpadlib test suite, I don't see the point of blocking a trivial change like this indefinitely. It would be possible to add a unit test that confirms this specific behaviour change functions correctly, but by design it depends posixpath.expanduser and ntpath.expanduser behaviour. The former uses getuid and the pwd module to get the correct directory when HOME doesn't exist, which make setting up a sensible test environment onerous. I could fake out the os module to test the ValueError is raised correctly, but really Python's coverage of the os.path module should be sufficient.

So to land it we just need to make sure the tests will still pass on (probably natty). If they do, +1. If not, then I hope that the reviewer will pick this up and fix it.

if launchpadlib_dir[:1] == '~':
would be clearer as
if launchpadlib_dir.startswith('~'):

Thanks Robert!

...I don't remember why I used a slice and not startswith.