Dungeons that are created in several of the recent development snapshots come without chests 100% of the time. To test this, you can create a world in 1.7 and find a dungeon that has at least one loot chest in it. Then, write down the coordinates and create a new world with the same seed in any version from 14w05b to 14w06b and travel to those coordinates. Even if the dungeon has chests in the 1.7 created world, it will not in a world created in the recent snapshots.