In the openQA test for TW transactional server, it sometimes (50%?) comes up
with /var and /etc read-only.

The journal shows:

Jul 30 14:51:59.631975 susetest systemd[1]: systemd-remount-fs.service: Main
process exited, code=exited, status=1/FAILURE
Jul 30 14:51:59.631989 susetest systemd[1]: systemd-remount-fs.service: Failed
with result 'exit-code'.
...
Jul 30 14:51:59.621373 susetest systemd-remount-fs[451]: /usr/bin/mount for /
exited with exit status 32.
...
Jul 30 14:51:59.650244 susetest systemd-remount-fs[457]: mount: /: mount point
is busy.
...
Jul 30 14:52:01.223177 susetest systemd[1]: Mounted /opt.
Jul 30 14:52:01.238240 susetest systemd[1]: Mounted /srv.
Jul 30 14:52:01.238624 susetest systemd[1]: Mounted /usr/local.
...
Jul 30 14:52:01.591134 susetest apparmor.systemd[485]: mkstemp: Read-only file
system

I don't see the failure happening in earlier snapshots, so this might be
something with the AppArmor update in 0729.

## Observation

openQA test in scenario
opensuse-Tumbleweed-DVD-x86_64-extra_tests_transactional_server@64bit fails in
[transactional_update](https://openqa.opensuse.org/tests/2488839/modules/transactional_update/steps/176)

## Test suite description
test transactional server.
Maintainer: Zaoliang Luo <zluo@suse.com>


## Reproducible

Fails since (at least) Build
[20220729](https://openqa.opensuse.org/tests/2488609)


## Expected result

Last good: [20220728](https://openqa.opensuse.org/tests/2486021) (or more
recent)


## Further details

Always latest result in this scenario:
[latest](https://openqa.opensuse.org/tests/latest?arch=x86_64&distri=opensuse&flavor=DVD&machine=64bit&test=extra_tests_transactional_server&version=Tumbleweed)