Comment # 15 on bug 1046158 from Egbert Eich

Some clarifications:

One difference is that older versions of this package (ie spec file) did not
use the %kernel_module_package macro for building a KMP.
Therefore the 2nd stage of the module package build which adds the signatures
never ran.
This version of spec file was used to created packages for SLES-12 SP1.

Karl and I got a bit further on this - since the discussion was started on
emailI never updated it.
Michal's comment #8 and the fact that this key never existed on Karl's system
made me google a bit and I cane up with:
http://opensuse.14.x6.nabble.com/Build-failure-due-to-a-missing-RSA-key-td5045532.html
Running an 'osc signkey --create' in this package directory will create a gpg
key for this package which will then be used to generate the ssl certificate
when needed.
This did work for Karl, however, now he has a different gpg key for this
package than the system wide one. So the next question was how to make use of
the system wide key. 
Since I was unable to answer this, I've added Adrian to Cc:, however, I've not
seen any feedback from him.
I do assume he's on vacation.