ConfigDrive with symlink inside breaks cloudbase-init

Hi guys, I just ran into an issue, I'm using `ConfigDrive` as `MetaData` service, the ISO was detected but `cloudbase-init` was not able to extract it *(cf. [1])*. The reason is that my `ConfigDrive` had a symlink `2015-10-15` pointing to `latest` and it seems to not be very appreciated on Windows *(my Windows knowledge is very poor)*. After removing the symlink, `cloudbase-init` was running as expected. There are two solutions *(IMHO)*: 1. Let's `cloudbase-init` detects symlinks and handle them properly 2. Add a note into the documentation saying that there should be no symlinks into the `ConfigDrive` Hope it helps. - *[1]*: http://paste.openstack.org/show/778950/