With the third beta of iOS 7.1, Apple included a feature that allows users to delete OTA ( over-the-air ) installation files that are installed automatically when an iPhone is connected to AC power.
Deletable installation files will allow users who do not wish to upgrade their devices to new versions of iOS to free up valuable space on their devices.
Users with iOS 7.1 beta 3 who have not installed the update will see it listed in the Settings menu, under General –> Usage, where it can be removed like any other app or file. The file can be deleted if it was downloaded over-the-air in the background or manually.
While over-the-air files can be deleted in iOS 7.1 beta 3, there is a possibility that this is a beta-only feature that will not make it into the final release of the software.