db: fix bug in tFiles.isOverlaps()
db: fix bug in tFiles.isOverlaps()

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