The city of Chicago has to get in line behind other creditors to collect traffic fines from people who got tickets after they filed for bankruptcy, a federal judge has held.In a written opinion last week in consolidated appeals in seven bankruptcy cases, U.S. District Judge Elaine Bucklo rejected the argument that the fines should be treated as administrative expenses under Section 503(b) of the U.S. Bankruptcy Code.Section 503(b) says administrative expenses include “the actual, necessary costs and expenses of …