Add missing shutdown for LevelDB.
Add missing shutdown for LevelDB.

archiecobbs/jsimpledb,archiecobbs/jsimpledb,tempbottle/jsimpledb,permazen/permazen,permazen/permazen,permazen/permazen,tempbottle/jsimpledb,tempbottle/jsimpledb,archiecobbs/jsimpledb