db: table: use Zap() instead of Purge() in cache when table removed
db: table: use Zap() instead of Purge() in cache when table removed

FactomProject/goleveldb,no2key/goleveldb,zzl0/goleveldb,btcsuite/goleveldb,syndtr/goleveldb,ngaut/goleveldb,hustbill/goleveldb,conseweb/goleveldb,rentongzhang/goleveldb,chai2010/goleveldb,trigrass2/goleveldb