FileAnalysis: optimizate connection set updating.

Don't need to be checking/updating that for sequential data input, which
won't be over multiple conns.

src/file_analysis/Manager.h

@@ -134,7 +134,8 @@ protected:
 	 *         fields.
 	 */
 	File* GetFile(const string& unique, Connection* conn = 0,
-	              AnalyzerTag::Tag tag = AnalyzerTag::Error);
+	              AnalyzerTag::Tag tag = AnalyzerTag::Error,
+	              bool update_conn = true);
 
 	/**
 	 * @return the File object mapped to \a file_id, or a null pointer if no