Fix for long UNC paths using opener.parse

[robmcmullen]

I'm not sure if this is the correct fix, but it's at least a workaround for long UNC paths. This code:

uri = r'\\?\UNC\VBOXSVR\work\stuff.xex'
fs, relpath = opener.parse(uri)
print relpath

was producing ?\N:\src\omnivore\UNC\VBOXSVR\work, so it was thinking that the UNC part was a parent directory rather than the UNC path specifier.