This is the first of a two-part column. The second part will be published on Tuesday.The contract that Centex Real Estate Corp. — the managing partner of Centex Homes — negotiated on behalf of the general partnership with McGreal Construction Co. for a project in Elgin, obligated McGreal to have Centex Real Estate and Centex Homes both designated as additional insureds under its general liability policy.But Centex Real Estate struck out in a coverage duel with McGreal’s carrier, Pekin Insurance Co.Pekin …