[#] 修复无文件，版本判断报错

RevokeMsgPatcher/Utils/FileUtil.cs

@@ -15,10 +15,18 @@ namespace RevokeMsgPatcher.Utils
         /// <param name="path"></param>
         /// <returns></returns>
         public static string GetFileVersion(string path)
+        {
+            if (File.Exists(path))
             {
                 FileVersionInfo fileVersionInfo = FileVersionInfo.GetVersionInfo(path);
                 return fileVersionInfo.FileVersion;
             }
+            else
+            {
+                return null;
+            }
+
+        }
 
         /// <summary>
         /// 计算文件SHA1