Bids requests failing if bidder missing

[AntoineJac]

Bug: Bids not trigger if a bidder is missing in the prebid.js file

Description

When settings the videoAdUnit parameters, if one of the bidder is not present in the Prebid.js file, it will make all the request crash... I have tested with the display and if a bidder is not present, other calls are still and correctly made.

Steps to reproduce

Please reach the following page where some random Appnexus and Rubicon parameters. The prebid.js has been built with only Rubicon adapter. As you will see no requests are made:
http://legba.alwaysdata.net/VideoR.html

I have used exactly the same code with a prebid.js built this time with Rubicon and Appnexus adapters. As you will see this time everything is ok:
http://legba.alwaysdata.net/VideoRA.html

Expected results

If a bidder is not present in the prebid.js tag, it should skip it but still make the call for the others bidders.

Actual results

All requests are skipped.

Platform details

The last version 0.21.0

Other information

[matthewlane]

I've made a note to fix this, though feel free to open a PR if you'd like. Thanks for the report