sbbs_t::sendfile() (used by JS bbs.send_file() and Baja FILE_SEND) would not

check the protocol.log (e.g. DSZ.LOG) for successful transfer even when the
protocol was so-configured in SCFG. Fixed.
Additionally, while sendfile() would return a proper boolean result based on
the errorlevel returned by the protocol driver process, the log and console
output would report success and statistics adjusted as though the xfer
was successful, regardless.