Fixed DownloadFile when file already exists

src/NzbDrone.Common.Test/Http/HttpClientFixture.cs

@@ -300,12 +300,12 @@ namespace NzbDrone.Common.Test.Http
         {
             var file = GetTempFilePath();
 
-            Assert.Throws<HttpException>(() => Subject.DownloadFile("https://download.readarr.com/wrongpath", file));
+            Assert.Throws<WebException>(() => Subject.DownloadFile("https://download.readarr.com/wrongpath", file));
 
             File.Exists(file).Should().BeFalse();
             File.Exists(file + ".part").Should().BeFalse();
 
-            ExceptionVerification.ExpectedWarns(1);
+            ExceptionVerification.ExpectedWarns(0);
         }
 
         [Test]

src/NzbDrone.Common/Http/HttpClient.cs

@@ -258,6 +258,11 @@ namespace NzbDrone.Common.Http
                 }
 
                 stopWatch.Stop();
+                if (File.Exists(fileName))
+                {
+                    File.Delete(fileName);
+                }
+
                 File.Move(fileNamePart, fileName);
                 _logger.Debug("Downloading Completed. took {0:0}s", stopWatch.Elapsed.Seconds);
             }
@@ -266,7 +271,7 @@ namespace NzbDrone.Common.Http
                 if (File.Exists(fileNamePart))
                 {
                     File.Delete(fileNamePart);
-                }  
+                }
             }
         }