Small changes required for PredictiveApriori.

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10200 e0a1b77d-ad91-4216-81b1-defd5f83fa92
Adapted for changes required as part of FastVector elimination crusade.

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10201 e0a1b77d-ad91-4216-81b1-defd5f83fa92