Failed to load xml module from jython

When we run jython unit test, we need to load xmlrunner and sax module. This works perfectly under the generic workbench, but does not work with NBI workbench.

Under an investigation, we have discovered that loading plug-in with name starting with "au.gov.ansto.bragg.cicada" will cause loading xml module as java package (instead of py module). Excluding any one of "au.gov.ansto.bragg.cicada.*" plug-in will not work. We need to disable loading ALL cicada plug-ins into jython to make loading xml becomes normal.