destroyHelper = function (o) {
			if (o && o.destroy) {
				o.destroy();
			}
			return null;
		}
Setter for a KeyFields array.

@private
@param {array} aKeyFields - array of KeyFields [{key: "CompanyCode", text: "ID"}, {key:"CompanyName", text : "Name"}]
@param {array} aKeyFieldsExclude - array of exclude KeyFields