Fixed NLog/NLog#609
Fixed NLog/NLog#609

Fixed CloseConnection() leaks IDbConnection objects as reported in NLog/NLog#609
czema/NLog,tohosnet/NLog,MoaidHathot/NLog,michaeljbaird/NLog,breyed/NLog,campbeb/NLog,fringebits/NLog,snakefoot/NLog,BrandonLegault/NLog,ArsenShnurkov/NLog,UgurAldanmaz/NLog,fringebits/NLog,bhaeussermann/NLog,AndreGleichner/NLog,littlesmilelove/NLog,czema/NLog,tetrodoxin/NLog,RichiCoder1/NLog,bjornbouetsmith/NLog,breyed/NLog,304NotModified/NLog,MartinTherriault/NLog,MartinTherriault/NLog,tohosnet/NLog,nazim9214/NLog,babymechanic/NLog,luigiberrettini/NLog,vbfox/NLog,UgurAldanmaz/NLog,fringebits/NLog,vladikk/NLog,bryjamus/NLog,bryjamus/NLog,thomkinson/NLog,BrandonLegault/NLog,ajayanandgit/NLog,vladikk/NLog,tmusico/NLog,matteobruni/NLog,czema/NLog,zbrad/NLog,FeodorFitsner/NLog,NLog/NLog,RichiCoder1/NLog,matteobruni/NLog,kevindaub/NLog,BrandonLegault/NLog,RRUZ/NLog,vladikk/NLog,ajayanandgit/NLog,kevindaub/NLog,sean-gilliam/NLog,thomkinson/NLog,BrandonLegault/NLog,ilya-g/NLog,rajeshgande/NLog,ArsenShnurkov/NLog,AndreGleichner/NLog,zbrad/NLog,tetrodoxin/NLog,hubo0831/NLog,littlesmilelove/NLog,luigiberrettini/NLog,vladikk/NLog,czema/NLog,thomkinson/NLog,vbfox/NLog,babymechanic/NLog,bhaeussermann/NLog,FeodorFitsner/NLog,thomkinson/NLog,Niklas-Peter/NLog,pwelter34/NLog,hubo0831/NLog,BrutalCode/NLog,ie-zero/NLog,nazim9214/NLog,ilya-g/NLog,MoaidHathot/NLog,michaeljbaird/NLog,RRUZ/NLog,ie-zero/NLog,rajeshgande/NLog,fringebits/NLog,BrutalCode/NLog,Niklas-Peter/NLog,bjornbouetsmith/NLog,pwelter34/NLog,tmusico/NLog,campbeb/NLog