Tweak the job script

Don't use with-fluids (I forget why), and enable core dumps.

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

@@ -96,7 +96,15 @@
 (let ((opts (parse-options (cdr (program-arguments)))))
   (match (assq-ref opts 'arguments)
     ((job)
-     (with-fluids ((%file-port-name-canonicalization 'none))
+     (with-exception-handler
+         (lambda (exn)
+           (simple-format #t "failed enabling core dumps: ~A\n" exn))
+       (lambda ()
+         (setrlimit 'core #f #f))
+       #:unwind? #t)
+
+     (fluid-set! %file-port-name-canonicalization 'none)
+
      (run-fibers
       (lambda ()
         (with-exception-handler
@@ -123,4 +131,4 @@
       #:hz 0
       #:parallelism 1
       ;; Drain to make sure there are no bugs with the use of fibers
-        #:drain? #t)))))
+      #:drain? #t))))