Problem regenerating gitlab docker images

[Christof Schmitt]

Hi,

while fixing the build problem with the system heimdal libraries, i am
also trying to establish a gitlab test for this build. This requires
adding the heimdal-multidev package to the Ubuntu images. Regenerating
the images now fails for CentOS7 and CentOS8, which should not changed.
I already fixed one problem for CentOS7 to avoid the conflict between
nettle and compat-nettle.

Now CentOS 7 fails with:
https://gitlab.com/samba-team/devel/samba/-/jobs/337893367
+ docker build -t samba-ci-centos7 --build-arg
'SHA1SUM=9dae5d8732853f0025bcf9528e94935f0e7ebada' bootstrap/generated-dists/centos7
Cannot connect to the Docker daemon at tcp://docker:2375. Is the docker daemon running?
ERROR: Job failed: exit code 1

And CentOS 8 with:
https://gitlab.com/samba-team/devel/samba/-/jobs/337893366
Error: 
 Problem: cannot install both glibc-common-2.28-42.el8_0.1.x86_64 and glibc-common-2.28-42.el8.1.x86_64
  - package glibc-langpack-en-2.28-42.el8_0.1.x86_64 requires glibc-common = 2.28-42.el8_0.1, but none of the providers can be installed
  - cannot install the best candidate for the job
  - conflicting requests

Does anybody have an idea how to address these?

Christof