Fix resource-pool-destroy-resource-exception

Raising the exception is more consistent, and avoids returning the
resource.

knots/resource-pool.scm

@@ -1351,8 +1351,7 @@ available.  Return the resource once PROC has returned."
                               'destroy
                               'return)
                           resource))
-                   (unless (resource-pool-destroy-resource-exception? exn)
+                   (raise-exception exn))
-                     (raise-exception exn)))
                (lambda ()
                  (with-exception-handler
                      (lambda (exn)