With all the speculation about a Democratic primary election challenger next year for Mayor Nutter -- Gov. Rendell? City Councilman Bill Green? Former GOP mayoral candidate Sam Katz? -- we're here to report that Nutter had one easy election night yesterday.  He was re-elected as leader of the 52nd Ward.  Nutter told us it was a swift meeting, "very smooth, very quiet," and he faced no challengers for his post.