gnu: tests: Fix unbound variable.

Record type descriptors were made private in
a143e92446, but a usage of them was
forgotten in the tests files.

* gnu/tests/web.scm (patchwork-initial-database-setup-service): Use
accessors to access field values instead of unexported type descriptor.

gnu/tests/web.scm

@@ -521,11 +521,7 @@ HTTP-PORT."
 ;;; Patchwork
 ;;;
 
-(define patchwork-initial-database-setup-service
-  (match-lambda
-    (($ <patchwork-database-configuration>
-        engine name user password host port)
-
+(define (patchwork-initial-database-setup-service configuration)
   (define start-gexp
     #~(lambda ()
         (let ((pid (primitive-fork))
@@ -540,10 +536,15 @@ HTTP-PORT."
                    (if (and
                         (zero?
                          (system* #$(file-append postgresql "/bin/createuser")
-                                     #$user))
+                                  #$(patchwork-database-configuration-user
+                                      configuration)))
                         (zero?
                          (system* #$(file-append postgresql "/bin/createdb")
-                                     "-O" #$user #$name)))
+                                  "-O"
+                                  #$(patchwork-database-configuration-user
+                                      configuration)
+                                  #$(patchwork-database-configuration-name
+                                      configuration))))
                        0
                        1)))
                 (lambda ()
@@ -556,7 +557,7 @@ HTTP-PORT."
    (start start-gexp)
    (stop #~(const #f))
    (respawn? #f)
-      (documentation "Setup patchwork database.")))))
+   (documentation "Setup patchwork database.")))
 
 (define (patchwork-os patchwork)
   (simple-operating-system