Fix leak that may occur when xmlnode_from_str fails
The failure may occur any time in the middle of parsing, and `xpd->current` may
not actually be pointing to the root of the parsed tree. Thus we need to walk
back up before freeing the xmlnode.
* @return @c FALSE if the specified account's privacy settings block the user or @c TRUE otherwise. The meaning of "block" is protocol-dependent and generally relates to status and/or sending of messages.