When Rep. Scott R. Drury held a news conference this morning announcing his gubernatorial campaign had switched to a bid for attorney general, he joined a mad dash of Democrats announcing, confirming or otherwise scrambling to mount campaigns to replace Lisa M. Madigan.But the Democrats have a bigger scramble ahead. They will have to turn their pledges into paperwork by the Dec. 4 filing deadline.On Friday, Madigan — the state’s longest-serving attorney general and the daughter of entrenched House Speaker …