修复bak文件重复时，before类型执行不成功的问题

Program.cs

@@ -105,7 +105,12 @@ namespace NetGitTool
                     {
                         content = reader.ReadToEnd();
                     }
-                    File.Move(file, file + ".bak");
+                    var bakfile = file + ".bak";
+                    //if (File.Exists(bakfile))
+                    //{
+                    //    File.Delete(bakfile);
+                    //}
+                    File.Move(file, bakfile);
                     Regex regex = new Regex("AssemblyFileVersion\\(\".*\"\\)");
                     content = regex.Replace(content, string.Format("AssemblyFileVersion(\"{0}\")", versionName));
                     using (var writer = File.CreateText(file))