Replace inner map with concurrent map in AdmissionControlGroup.
Replace inner map with concurrent map in AdmissionControlGroup.

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