CyanogenMod 12.1 ERROR "KERNEL IS NOT SEANDROID ENFORCING SET WARRANTY BIT: KERNEL"

Hi. I am working on a brand new Samsung SM-G900F i.e. a Samsung Galaxy s5.
I shall explain how I have got where I have got below - which ended up with a rooted, working phone running CyanogenMod 12.1, Android 5.1.1 and with the GAPPS (Google Apps) on it, but the question is simply this: -

"How do I get rid of the error message that appears when I boot at the top left of the screen

KERNEL IS NOT SEANDROID ENFORCING
SET WARRANTY BIT: KERNEL
?"

I have set out the following in detail, in case the sequence of steps I undertook will assist other users, or enable them to recognise whereabouts in the sequence they are experiencing errors.

1) I am in the UK. The phone is a brnd new, boxed Samsung SM-G900F which uses LTE (it says so on the box, whatever LTE is).
2) The phone is not network locked: I bought it from MobilePhonesDirect (a big online retailer here in the UK) but I have a Vodafone (UK) SIM card in it, and it has hitherto worked. I am porting a number across to it such port taking effect today.
3) On the new phone I downloaded an upgrade to Android 5.0. I then encrypted the phone which took less than an hour, but quite a long time nonetheless.
4) This wasn't good enough! I wanted Android 5.1 or Android 5.1.1, so ....
5) I connected the phone to my Windows 10 PC via USB, and I attempted to use Kies. This told me to use a newer product called Smart Switch to communicate with the phone. I installed this and was able to communicate.
6) I used ODIN 3.07 to flash things to the phone. I flashed CF-Auto-Root-klte-kltejv-smg900fq and I successfully rooted the phone. Upon boot it was still running Android 5.0 and it was still encrypted.
7) I flashed ClockWorkMod (CWM) to the phone, this version: g900f-cwm-recovery-6.0.4.7
8) I flashed the following zip files to the phone [TN]-VM12.1-20150327-2.0.0-klte and gapps-5.1.x-20150324-minimal-edition-signed.
9) The phone started to boot, but I got the Cyanogenmod 12.1 "Encryption Unsuccessful" message and it would not get past that.
10) I read up. I had used the wrong Cyanogenmod file, I think. I then discovered that as the phone would not boot I was unable to get any files onto it.
11) I then, from CWM, did a factory reset, wiped the cache, and wiped the Dalvik cache
12) I discovered the wonderful, wonderful ADB feature in CMW. I managed to find a piece of software called fastboot.zip. Eventually I worked out the sequence of commands and the syntax (thanks to a YouTube video which I wished to link to but I cannot find what it was I used last night!).
12) I flashed these two slightly different CyanogenMod 12.1 / GAPPS files to the phone: cm-12.1-20150428-UNOFFICIAL-klte.zip and gapps-lpmr1-20150324-signed.zip.
13) It still had errors. I went back to CWM and I "unmounted" and "formatted" this, that and everything, and I eventually got those two zips to work.
13) The phone now functions effectively, BUT ....
14) I still get the error message
KERNEL IS NOT SEANDROID ENFORCING
SET WARRANTY BIT: KERNEL

The above took me about 4 and a half hours in total, watching YouTube tutorial videos etc etc.
I am very grateful for all of those who share their knowledge. I would love it if someone knew how to get rid of that error message. I read something about it being Samsung Knox. I tried to run a command line command from a terminal emulator on the phone, but I got an error message.

BlameTheMachines
(to quote Duran Duran!)