In a large skillet, heat the remaining 2 tablespoons of olive oil. Add the pancetta and cook over moderately high heat until lightly browned, 3 to 4 minutes. Add the leeks and cook until they begin to soften, 3 to 4 minutes. Add the lentils and cook, stirring, for 1 minute. Stir in the vinaigrette and chopped parsley, thyme and savory. Season with salt and pepper.