Fix kvm-dependency package

servo-build-dependencies/kvm.sls

@@ -1,10 +1,8 @@
 kvm-dependencies:
   pkg.installed:
     - pkgs:
-      # We don’t actually use the contents of this package,
-      # installing it makes /dev/kvm be usable by the 'kvm' Unix group
-      # (and makes that group exist).
-      - libvirt-bin
+      # Also creates the 'kvm' group and gives it permissions to /dev/kvm
+      - qemu-kvm
 
 kvm-group:
   user.present: