vdr 2.1.2 buildfix

[stefansaraev]

a trivial one. from vdr changelog:

• The functions OpenVideoFile(), RenameVideoFile(), RemoveVideoFile(), VideoFileSpaceAvailable(), VideoDiskSpace(), RemoveEmptyVideoDirectories(), IsOnVideoDirectoryFileSystem() and PrefixVideoFileName() are now static members of cVideoDirectory and need to be called with the proper prefix.
• The name of the video directory is now available through cVideoDirectory::Name().

[pipelka]

Thanks. I'm still using 2.0.1.