remove duplicate line in AppNexus adapter

[benjaminclot]

• added reserve price parameter
• removed duplicate jptCall = utils.tryAppendQueryString(jptCall, 'code', inventoryCode);

[mkendall07]

@benjaminclot
You actually don't need this code to be added. You can already add reserve into the AppNexus bidder params and it is automatically added to the query. Any key/value will work: https://github.com/benjaminclot/Prebid.js/blob/4e0e46c9cfc035e46e7d10a66b48ca8b212b7f37/src/adapters/appnexus.js#L117

[benjaminclot]

My bad, I didn't see this part.
But the duplicate line is still valid I guess :)

[mkendall07]

Yep. If you remove the other code I'll merge.

[benjaminclot]

Done.