tests/kola: rework derived kernel-replace

Now use dnf download to go ahead and download the RPMs that we'll
override replace in the container build.

Also, for Fedora, stop hardcoding the kernel to use and default to
using the latest kernel in the N-1 release of Fedora. It guarantees
it will be a different kernel and also is a moving target, which
means it won't get grotesquely out of date.

tests/kola/rpm-ostree/kernel-replace

@@ -71,46 +71,44 @@ build_base_ociarchive() {
 }
 
 build_derived_ociarchive() {
+    # do the container build in a temporary context directory
+    contextdir=$(mktemp -d)
+    pushd ${contextdir}
+
+    case "$OS_ID" in
+      rhcos|scos|rhel|centos)
+        c9s_mirror="https://mirror.stream.centos.org/9-stream/BaseOS/${arch}/os"
+        # we're probably already on CentOS and running the latest kernel. so
+        # here we need to instead pick whatever the latest that's *not* the same
+        dnf_opts="--repofrompath=tmp,"${c9s_mirror}" --disablerepo=* --enablerepo tmp"
+        kver=$(dnf repoquery $dnf_opts kernel --qf '%{EVR}' | \
+                  grep -v "$(rpm -q kernel --qf '%{EVR}')" | tail -n1)
+        # For some reason for now `kernel-modules-extra` doesn't resolve so we need to explicitly ask for it here
+        dnf download $dnf_opts --resolve "kernel-${kver}" "kernel-modules-extra-${kver}"
+        ;;
+      fedora)
+        VERSION_ID=$(. /etc/os-release; echo $VERSION_ID)
+        previous_version_id=$((VERSION_ID - 1))
+        dnf download --releasever "${previous_version_id}" --resolve \
+          --disablerepo=* --enablerepo=updates --enablerepo=fedora kernel
+        kver=$(rpm -qp --qf '%{EVR}' ./kernel-core*rpm)
+        ;;
+      *)
+        echo "Unknown OS_ID: ${OS_ID}"
+        exit 1
+        ;;
+    esac
+
     # we only want to query repos once but need the info on multiple boots, so write out state to /var
-    if [ ! -f /var/kola-kernel.evr ]; then
-      case "$OS_ID" in
-        rhcos|scos|rhel|centos)
-          c9s_mirror="https://mirror.stream.centos.org/9-stream/BaseOS/${arch}/os"
-          # we're probably already on CentOS and running the latest kernel. so
-          # here we need to instead pick whatever the latest that's *not* the same
-          kver=$(dnf repoquery kernel --qf '%{EVR}' --repofrompath=tmp,"${c9s_mirror}" --disablerepo '*' --enablerepo tmp | \
-                    grep -v "$(rpm -q kernel --qf '%{EVR}')" | tail -n1)
-          kver="${kver}.${arch}"
-          url="${c9s_mirror}/Packages/kernel"
-          ;;
-        fedora)
-          # to get the version to use: koji latest-pkg f40 kernel
-          # XXX: once we can rely on dnf in FCOS, use repoquery also here
-          kver="6.8.5-301.fc40.${arch}"
-          url="https://kojipkgs.fedoraproject.org//packages/kernel/6.8.5/301.fc40/${arch}/kernel"
-          ;;
-        *)
-          echo "Unknown OS_ID: ${OS_ID}"
-          exit 1
-          ;;
-      esac
-      echo "$kver" > /var/kola-kernel.evr
-      echo "$url" > /var/kola-kernel.url
-    else
-      kver=$(cat /var/kola-kernel.evr)
-      url=$(cat /var/kola-kernel.url)
-    fi
+    echo "$kver" > /var/kola-kernel.evr
 
-    td=$(mktemp -d)
-    pushd ${td}
     cat > Containerfile << EOF
 FROM $imagespec
-RUN rpm-ostree override replace \
-    $url-{,core-,modules-,modules-core-,modules-extra-}$kver.rpm && \
+RUN rpm-ostree override replace /tmp/buildcontext/*rpm && \
     rpm-ostree cleanup -m && \
     ostree container commit
 EOF
-    podman build --net=host -t "${derived_imagespec}" --squash .
+    podman build --volume $PWD:/tmp/buildcontext:z -t "${derived_imagespec}" --squash .
     popd
 }
 
@@ -141,7 +139,8 @@ case "${AUTOPKGTEST_REBOOT_MARK:-}" in
     /tmp/autopkgtest-reboot 2
     ;;
   2)
-    un=$(uname -r)
+    kver="$(cat /var/kola-kernel.evr).${arch}" # expected
+    un=$(uname -r)                             # detected
     if test "$un" != "$kver"; then
       echo "Expected kernel $kver but found $un"
       exit 1