Detach the database setup from the main guix-data-service process

This will allow restarting them independently, leaving it up to the operator
to ensure that all processes are compatible.

scripts/guix-data-service-process-jobs.in

@@ -65,6 +65,8 @@
    %default-options))
 
 (let ((opts (parse-options (cdr (program-arguments)))))
+  (run-sqitch)
+
   (with-postgresql-connection
    "process-jobs"
    (lambda (conn)