Don't parse omgwtfnzb if no results are returned

couchpotato/core/media/_base/providers/nzb/omgwtfnzbs.py

@@ -44,6 +44,7 @@ class Base(NZBProvider, RSS):
 
         nzbs = self.getJsonData(self.urls['search'] % params)
 
+        if isinstance(nzbs, list):
             for nzb in nzbs:
 
                 results.append({