Reenable storprep with a StorPool image

Change-Id: If713f18c682d7714d33f88a15ead73ee0daaaa4d
diff --git a/playbooks/sp-init.yaml b/playbooks/sp-init.yaml
index 4eab4ad..05914f8 100644
--- a/playbooks/sp-init.yaml
+++ b/playbooks/sp-init.yaml
@@ -14,7 +14,7 @@
 
     - name: ctrl-sp-run-storprep
       shell:
-        cmd: echo sh '{{ storprep_filename }}' -- -n lab-charmed-testing-storage -s lab-vlan400 -- {{ host_id }}
+        cmd: sh '{{ storprep_filename }}' -- -n lab-charmed-testing-storage -s lab-vlan400 -- {{ host_id }}
 
     - name: ctrl-sp-rm-storprep
       shell: