Redire is a Cydia tweak that promises to restore the Camera in your lock screen to the way it was before 5.1. Just install the tweak and respring. From now on you can tap the home button twice on your locked iPhone, press the camera button, and be whisked away to the camera app, just for old times sake.

The tweak is free on Big Boss repo

*Credits to iJailbreak fro info and pics!