services: swap: Use 'restart-on-EINTR'.

* gnu/services/base.scm (swap-service)[start, stop]: Use 'restart-on-EINTR'.
* guix/build/syscalls.scm (swapoff): Fix typo in 'throw' arguments.

gnu/services/base.scm

@@ -851,10 +851,10 @@ (define requirement
              (requirement `(udev ,@requirement))
              (documentation "Enable the given swap device.")
              (start #~(lambda ()
-                        (swapon #$device)
+                        (restart-on-EINTR (swapon #$device))
                         #t))
              (stop #~(lambda _
-                       (swapoff #$device)
+                       (restart-on-EINTR (swapoff #$device))
                        #f))
              (respawn? #f)))))
 

guix/build/syscalls.scm

@@ -218,7 +218,7 @@ (define swapoff
       (let ((ret (proc (string->pointer device)))
             (err (errno)))
         (unless (zero? ret)
-          (throw 'system-error "swapff" "~S: ~A"
+          (throw 'system-error "swapoff" "~S: ~A"
                  (list device (strerror err))
                  (list err)))))))