USHIFT-2241: use unique repo name when extracting container images

Reusing the same temporary repo name for different repository locations
can introduce issues if the dnf cache is not updated. Use the base name
of the repository URL as a unique name.

test/bin/build_images.sh

@@ -29,13 +29,13 @@ extract_container_images() {
     local -r version=$1
     local -r repo_url=$2
     local -r outfile=$3
-    local -r repo_name="microshift-extract-images"
 
     echo "Extracting images from ${version}"
     mkdir -p "${IMAGEDIR}/release-info-rpms"
     pushd "${IMAGEDIR}/release-info-rpms"
     dnf_options=""
     if [[ -n ${repo_url} ]]; then
+        local -r repo_name="$(basename "${repo_url}")"
         dnf_options="--repofrompath ${repo_name},${repo_url} --repo ${repo_name}"
     fi
     # shellcheck disable=SC2086  # double quotes