Remove unnecessary N/A checks (converter changes them to null)

MediaBrowser.Providers/Plugins/Omdb/OmdbImageProvider.cs

@@ -55,7 +55,7 @@ namespace MediaBrowser.Providers.Plugins.Omdb
 
             var rootObject = await _omdbProvider.GetRootObject(imdbId, cancellationToken).ConfigureAwait(false);
 
-            if (string.IsNullOrEmpty(rootObject.Poster) || string.Equals("N/A", rootObject.Poster, StringComparison.OrdinalIgnoreCase))
+            if (string.IsNullOrEmpty(rootObject.Poster))
             {
                 return Enumerable.Empty<RemoteImageInfo>();
             }

MediaBrowser.Providers/Plugins/Omdb/OmdbItemProvider.cs

@@ -205,7 +205,7 @@ namespace MediaBrowser.Providers.Plugins.Omdb
                 item.PremiereDate = released;
             }
 
-            if (!string.IsNullOrWhiteSpace(result.Poster) && !string.Equals(result.Poster, "N/A", StringComparison.OrdinalIgnoreCase))
+            if (!string.IsNullOrWhiteSpace(result.Poster))
             {
                 item.ImageUrl = result.Poster;
             }