leveldb - fix ecx warning that it is not initialized, intilize it with 0
leveldb - fix ecx warning that it is not initialized, intilize it with 0

info: if we do not specify U then variable type would be signed int

this commit as well as other commits should be pulled to bitcoin's leveldb

cevap/ion,cevap/ion,ionomy/ion,ionomy/ion,ionomy/ion,cevap/ion,cevap/ion,cevap/ion,ionomy/ion,ionomy/ion,cevap/ion,ionomy/ion