test/cases: use correct OS_VARIANT for CentOS Stream 9

Correct name is 'centos-stream9'
See 'osinfo-query os'

test/cases/ostree-ng.sh

@@ -136,7 +136,7 @@ case "${ID}-${VERSION_ID}" in
         ;;
     "centos-9")
         OSTREE_REF="test/centos/9/${ARCH}/edge"
-        OS_VARIANT="centos9"
+        OS_VARIANT="centos-stream9"
         USER_IN_UPGRADE_BP="false"
         INSTALLER_PATH="/run/install/repo/ostree/repo"
         ;;

test/cases/ostree-raw-image.sh

@@ -110,7 +110,7 @@ case "${ID}-${VERSION_ID}" in
         ;;
     "centos-9")
         OSTREE_REF="centos/9/${ARCH}/edge"
-        OS_VARIANT="centos9"
+        OS_VARIANT="centos-stream9"
         ;;
     *)
         echo "unsupported distro: ${ID}-${VERSION_ID}"

test/cases/ostree-simplified-installer.sh

@@ -119,7 +119,7 @@ case "${ID}-${VERSION_ID}" in
         ;;
     "centos-9")
         OSTREE_REF="centos/9/${ARCH}/edge"
-        OS_VARIANT="rhel9-unknown"
+        OS_VARIANT="centos-stream9"
         ;;
     *)
         echo "unsupported distro: ${ID}-${VERSION_ID}"

test/cases/ostree.sh

@@ -62,7 +62,7 @@ case "${ID}-${VERSION_ID}" in
     "centos-9")
         IMAGE_TYPE=edge-commit
         OSTREE_REF="centos/9/${ARCH}/edge"
-        OS_VARIANT="centos9"
+        OS_VARIANT="centos-stream9"
         USER_IN_COMMIT="true"
         # This should be changed once we get centos-9 runners
         BOOT_LOCATION="${COMPOSE_URL:-}/compose/BaseOS/x86_64/os/"