jenkins vary slave: allow controller or slave to be null
jenkins vary slave: allow controller or slave to be null

flybird119/voltdb,VoltDB/voltdb,paulmartel/voltdb,zuowang/voltdb,flybird119/voltdb,wolffcm/voltdb,wolffcm/voltdb,simonzhangsm/voltdb,kumarrus/voltdb,creative-quant/voltdb,deerwalk/voltdb,wolffcm/voltdb,simonzhangsm/voltdb,VoltDB/voltdb,kumarrus/voltdb,zuowang/voltdb,simonzhangsm/voltdb,paulmartel/voltdb,migue/voltdb,zuowang/voltdb,flybird119/voltdb,kumarrus/voltdb,migue/voltdb,ingted/voltdb,ingted/voltdb,ingted/voltdb,VoltDB/voltdb,paulmartel/voltdb,creative-quant/voltdb,simonzhangsm/voltdb,paulmartel/voltdb,zuowang/voltdb,wolffcm/voltdb,migue/voltdb,VoltDB/voltdb,deerwalk/voltdb,paulmartel/voltdb,VoltDB/voltdb,kumarrus/voltdb,simonzhangsm/voltdb,migue/voltdb,ingted/voltdb,wolffcm/voltdb,creative-quant/voltdb,flybird119/voltdb,paulmartel/voltdb,kumarrus/voltdb,deerwalk/voltdb,flybird119/voltdb,zuowang/voltdb,wolffcm/voltdb,migue/voltdb,kumarrus/voltdb,migue/voltdb,flybird119/voltdb,deerwalk/voltdb,flybird119/voltdb,simonzhangsm/voltdb,deerwalk/voltdb,paulmartel/voltdb,ingted/voltdb,deerwalk/voltdb,migue/voltdb,kumarrus/voltdb,ingted/voltdb,simonzhangsm/voltdb,migue/voltdb,wolffcm/voltdb,zuowang/voltdb,ingted/voltdb,VoltDB/voltdb,creative-quant/voltdb,simonzhangsm/voltdb,creative-quant/voltdb,wolffcm/voltdb,deerwalk/voltdb,zuowang/voltdb,creative-quant/voltdb,ingted/voltdb,flybird119/voltdb,zuowang/voltdb,kumarrus/voltdb,deerwalk/voltdb,paulmartel/voltdb,creative-quant/voltdb,creative-quant/voltdb,VoltDB/voltdb