Modified code to clear only user preference from local storage while running DbMonitor tests.
Modified code to clear only user preference from local storage while
running DbMonitor tests.

migue/voltdb,VoltDB/voltdb,simonzhangsm/voltdb,deerwalk/voltdb,migue/voltdb,migue/voltdb,VoltDB/voltdb,migue/voltdb,deerwalk/voltdb,VoltDB/voltdb,simonzhangsm/voltdb,migue/voltdb,simonzhangsm/voltdb,simonzhangsm/voltdb,simonzhangsm/voltdb,migue/voltdb,migue/voltdb,simonzhangsm/voltdb,deerwalk/voltdb,migue/voltdb,deerwalk/voltdb,simonzhangsm/voltdb,VoltDB/voltdb,deerwalk/voltdb,VoltDB/voltdb,simonzhangsm/voltdb,deerwalk/voltdb,VoltDB/voltdb,deerwalk/voltdb,VoltDB/voltdb,deerwalk/voltdb