ci: don't try to install kernel-devel on qubes

It's already available there.

.gitlab-ci.yml

@@ -24,8 +24,9 @@ checks:tests:
       # We are now going to force the installation of the specific kernel-devel version
       # that matches the current kernel.  If unavailable, the test should fail now.
       # Ideally the VM image ships with a kernel-devel package that matches the
-      # booted kernel.
-      sudo dnf install -y zfs kernel-core-$kver kernel-devel-$kver
+      # booted kernel. This is already the case for Qubes DispVM.
+      uname -r | grep -q qubes || sudo dnf install -y kernel-core-$kver kernel-devel-$kver
+      sudo dnf install -y zfs
       # Proactively load the kernel module with the right size ARC to prevent memory
       # starvation during integration tests.  Otherwise the ARC will not reduce
       # itself unless there's memory pressure, and the system will fail to request