def readlink(self, path):
return SFTP_OP_UNSUPPORTED<EOL>
Return the target of a symbolic link (or shortcut) on the server.
If the specified path doesn't refer to a symbolic link, an error
should be returned.

@param path: path (relative or absolute) of the symbolic link.
@type path: str
@return: the target path of the symbolic link, or an error code like
    L{SFTP_NO_SUCH_FILE}.
@rtype: str I{or error code}