Yeah. You can do that. But what about that safety update? Don't you wanna wan't that?
Not sure if this will work for everyone else but up until today I had the same issue. I went to Settings > Applications > All > Security Update and hit clear data. Instantly the update prompt came back and when I hit confirm this time it worked.
Hope it works for some others!
This Is the Reply from the Samsung Forum on the s4 Security Policy Update
We are currently upgrading Security Enhancements for Android which will check apps for malicious code and security risks. However some customers appear to be experiencing a connection issue with the upgrade server which we are investigating.
Please be assured that there is nothing to be concerned about and we are working on resolving the issue.