Add GalleryProvider.cancelRequest(int), fix SpiderQueen.request(int, boolean)

app/src/main/java/com/hippo/ehviewer/gallery/EhGalleryProvider.java

@@ -99,6 +99,13 @@ public class EhGalleryProvider extends GalleryProvider implements SpiderQueen.On
         }
     }
 
+    @Override
+    public void cancelRequest(int index) {
+        if (mSpiderQueen != null) {
+            mSpiderQueen.cancelRequest(index);
+        }
+    }
+
     @Override
     public String getError() {
         if (mSpiderQueen != null) {