Fix fragments without empty constructor

app/src/main/java/org/schabi/newpipe/fragments/detail/DescriptionFragment.java

@@ -30,6 +30,9 @@ public class DescriptionFragment extends BaseDescriptionFragment {
         this.streamInfo = streamInfo;
     }
 
+    public DescriptionFragment() {
+    }
+
 
     @Nullable
     @Override

app/src/main/java/org/schabi/newpipe/fragments/list/channel/ChannelAboutFragment.java

@@ -30,6 +30,8 @@ public class ChannelAboutFragment extends BaseDescriptionFragment {
         this.channelInfo = channelInfo;
     }
 
+    public ChannelAboutFragment() {
+    }
 
     @Override
     protected void initViews(final View rootView, final Bundle savedInstanceState) {