[MERGE] bzrlib.osutils fixes

[John Arbash Meinel]

John Arbash Meinel has voted +1 (conditional).
Status is now: Conditionally approved
Comment:
Some small things....

_directory_kind was really a misfeature. We were trying to re-use the 
same string object, but it turns out that python automatically interns 
any strings that look like identifiers (\w+). I think the code would be 
a lot clearer if we just used 'directory' everywhere like we use 'file'.

I understand why tuple versus list doesn't matter, (because we just 
re-generate it as a different tuple later) but it may be better to have 
an explicit comment about it.

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C45EEE2C5.5080008%40hlabs.spb.ru%3E