Merge pull request #4773 from Artiume/patch-10

Remove opf extension for book types

(cherry picked from commit e7ae7124372969802651018ef9666a2acbed211e)
Signed-off-by: Joshua M. Boniface <joshua@boniface.me>

Emby.Server.Implementations/Library/Resolvers/Books/BookResolver.cs

@@ -11,7 +11,7 @@ namespace Emby.Server.Implementations.Library.Resolvers.Books
 {
     public class BookResolver : MediaBrowser.Controller.Resolvers.ItemResolver<Book>
     {
-        private readonly string[] _validExtensions = { ".azw", ".azw3", ".cb7", ".cbr", ".cbt", ".cbz", ".epub", ".mobi", ".opf", ".pdf" };
+        private readonly string[] _validExtensions = { ".azw", ".azw3", ".cb7", ".cbr", ".cbt", ".cbz", ".epub", ".mobi", ".pdf" };
 
         protected override Book Resolve(ItemResolveArgs args)
         {