Update xtrabackup to 2.4

For the updating of MySQL package we need also update
percona-xtrabackup

Closes-Bug: PROD-36708
Change-Id: Iaa860cc3ff348c46d3d5b7ff7c6f2c28a1b248d1
(cherry picked from commit 8566c5740d127f4f0e536e571521d3b39250a437)
diff --git a/tests/pillar/repo_percona.sls b/tests/pillar/repo_percona.sls
new file mode 100644
index 0000000..0272834
--- /dev/null
+++ b/tests/pillar/repo_percona.sls
@@ -0,0 +1,10 @@
+linux:
+  system:
+    enabled: true
+    repo:
+      percona:
+        source: "deb [arch=amd64] http://mirror.mirantis.com/testing/percona/{{ grains.get('oscodename') }} {{ grains.get('oscodename') }} main"
+        key_url: "http://percona.com/downloads/deb-percona-keyring.gpg"
+      extra:
+        source: "deb http://mirror.mirantis.com/testing/extra/{{ grains.get('oscodename') }} {{ grains.get('oscodename') }} main"
+        key_url: "http://mirror.mirantis.com/testing/extra/{{ grains.get('oscodename') }}/archive-extra.key"