lint: 'check-derivation' fully disables grafts.

Previously grafting could take place indirectly, for instance when
lowering origins.

* guix/scripts/lint.scm (check-derivation)[try]: Parameterize
'%graft?'.

guix/scripts/lint.scm

@@ -33,6 +33,7 @@
   #:use-module (guix packages)
   #:use-module (guix licenses)
   #:use-module (guix records)
+  #:use-module (guix grafts)
   #:use-module (guix ui)
   #:use-module (guix upstream)
   #:use-module (guix utils)
@@ -789,6 +790,7 @@ descriptions maintained upstream."
                                          (condition-message c)))))
           (with-store store
             ;; Disable grafts since it can entail rebuilds.
+            (parameterize ((%graft? #f))
               (package-derivation store package system #:graft? #f)
 
               ;; If there's a replacement, make sure we can compute its
@@ -797,7 +799,7 @@ descriptions maintained upstream."
                 (#f #t)
                 (replacement
                  (package-derivation store replacement system
-                                   #:graft? #f))))))
+                                     #:graft? #f)))))))
       (lambda args
         (emit-warning package
                       (format #f (G_ "failed to create ~a derivation: ~s")