Add sysbench package

This is required from the memory benchmarks.

Author: jovial

elements/cardiff/package-installs.yaml

@@ -1 +1,2 @@
 lsb_release:
+sysbench:

elements/cardiff/pkg-map

@@ -5,6 +5,7 @@
     }
   },
   "default": {
-    "lsb_release": ""
+    "lsb_release": "",
+    "sysbench": "sysbench"
   }
 }