The original PERL script cds/common/scritps/beckhoff_gang_whiten no longer works on the new Debian8 machines. As per ECR E1700056, when we find broken PERL scripts we re-write them in PYTHON.

beckhoff_gang_whiten is now a python script. I think there was a bug in the PERL scipt which with an invalid argument could cause FE whitening digital switching without its corresponding Beckhoff analog switching, which I fixed in the new code. There was also some redundency in the code which I removed.

Sheila tested the new code on ASC, it appears to work.