DEVEX-2013 --allow-ssh fixes (#750)
DEVEX-2013 --allow-ssh fixes (#750)

* Do not delete elements from list while iterating

* Fix help message
dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit,dnanexus/dx-toolkit