Add qemu-utils to n-cpu debs

Qemu-utils is needed by nova-cpu, we are hitting issues with this in
multi node testing where fewer services are installed on the second
node.

Change-Id: I4b0a217a252c7862014443230dda2bcced355c93
diff --git a/files/debs/n-cpu b/files/debs/n-cpu
index a82304d..534b1c1 100644
--- a/files/debs/n-cpu
+++ b/files/debs/n-cpu
@@ -1,3 +1,4 @@
+qemu-utils
 # Stuff for diablo volumes
 lvm2
 open-iscsi