CADC: check job has correct state for e-transfer
CADC: check for files already in scratch directory
CADC: omit unnecessary e-transfer error logging

Since this routine is now run under the ErrorDecorator
(which logs exceptions) we do not need to call logger.error
as well as raising an exception.
CADC: copy files to e-transfer dir and set state

This completes the e-transfer sending function.  The e-transfer
group (for file permissions) has been added to the configuration
file.
CADC: use symbolic name for passwd struct entry