MediaInfo Dispose only when handle was created.

src/NzbDrone.Core/MediaFiles/MediaInfo/MediaInfoLib.cs

@@ -72,13 +72,19 @@ namespace NzbDrone.Core.MediaFiles.MediaInfo
         }
 
         ~MediaInfo()
+        {
+            if (_handle != IntPtr.Zero)
             {
                 MediaInfo_Delete(_handle);
             }
+        }
 
         public void Dispose()
+        {
+            if (_handle != IntPtr.Zero)
             {
                 MediaInfo_Delete(_handle);
+            }
             GC.SuppressFinalize(this);
         }