Revert "don't allow null or undefined bid properties" (prebid#2886)

* Revert "New Adapter ZEDO (prebid#2872)"

This reverts commit 8eedfc3.

* Revert "don't allow null or undefined bid properties (prebid#2865)"

This reverts commit f5170d9.

src/adapters/bidderFactory.js

@@ -381,7 +381,7 @@ function validBidSize(adUnitCode, bid, bidRequests) {
 export function isValid(adUnitCode, bid, bidRequests) {
   function hasValidKeys() {
     let bidKeys = Object.keys(bid);
-    return COMMON_BID_RESPONSE_KEYS.every(key => includes(bidKeys, key) && !includes([undefined, null], bid[key]));
+    return COMMON_BID_RESPONSE_KEYS.every(key => includes(bidKeys, key));
   }
 
   function errorMessage(msg) {

test/spec/unit/core/bidderFactory_spec.js

@@ -427,36 +427,6 @@ describe('bidders created by newBidder', () => {
 
       expect(logErrorSpy.calledOnce).to.equal(true);
     });
-
-    it('should logError when required bid response params are undefined', () => {
-      const bidder = newBidder(spec);
-
-      const bid = {
-        'ad': 'creative',
-        'cpm': '1.99',
-        'width': 300,
-        'height': 250,
-        'requestId': '1',
-        'creativeId': 'some-id',
-        'currency': undefined,
-        'netRevenue': true,
-        'ttl': 360
-      };
-
-      spec.isBidRequestValid.returns(true);
-      spec.buildRequests.returns({
-        method: 'POST',
-        url: 'test.url.com',
-        data: {}
-      });
-      spec.getUserSyncs.returns([]);
-
-      spec.interpretResponse.returns(bid);
-
-      bidder.callBids(MOCK_BIDS_REQUEST, addBidResponseStub, doneStub, ajaxStub);
-
-      expect(logErrorSpy.calledOnce).to.equal(true);
-    });
   });
 
   describe('when the ajax call fails', () => {