openchange: return proper url for folders with non-ascii chars

toManyRelationshipKeysWithNamespaces applies asCSSIdentifier function
to the names which are already "Imap4Encoded". So we need to remove the
CSSIdentifier function first and then "Imap4Decode" to get the real name.

Once we have the real name, to create the url we have to use the same
logic as the function that creates the folder and creates this url for
the first time (this function is createRootSecondaryFolderWithFID)
which is to apply, in this order:

- asCSSIdentifier
- stringByEncodingImap4FolderName
- stringByAddingPercentEscapesUsingEncoding