Ok, If I comment out that line preview for videos from search does not work, because this URL is requested (and it fails):

http://muppet.inez.wikia-dev.com/api.php?format=json&action=videopreview&title=Disney%27s+%22The+Muppets%22+-+Kermit+the+Frog+Interview

instead of:
http://muppet.inez.wikia-dev.com/api.php?format=json&action=videopreview&provider=wikia&title=Disney%27s+%22The+Muppets%22+-+Kermit+the+Frog+Interview

I'm still figuring out if this information should be added in that api - since all videos from search are wikia videos than it's redundant I believe.