updated upgrade file for release 1.7.2
updated upgrade file for release 1.7.2

prolixtechnikos/LiipImagineBundle,robfrawley/LiipImagineBundle,robfrawley/LiipImagineBundle,prolixtechnikos/LiipImagineBundle,liip/LiipImagineBundle,liip/LiipImagineBundle,prolixtechnikos/LiipImagineBundle