gnu: samba/fixed: Update to 4.15.13.

* gnu/packages/samba.scm (samba/fixed-patched): New variable.
(samba/fixed): Add replacement for samba/fixed-patched.

gnu/packages/samba.scm

@@ -295,7 +295,9 @@ (define-public samba
 (define-public samba/fixed
   ;; Version that rarely changes, depended on by libsoup.
   (hidden-package
-   (package/inherit samba
+   (package
+     (inherit samba)
+     (replacement samba/fixed-patched)
      (version "4.15.3")
      (source
       (origin
@@ -319,6 +321,18 @@ (define-public samba/fixed
             libxslt
             libxml2)))))
 
+(define-public samba/fixed-patched
+  (package
+    (inherit samba/fixed)
+    (version "4.15.13")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "https://download.samba.org/pub/samba/stable/"
+                           "samba-" version ".tar.gz"))
+       (sha256
+        (base32 "0s29vzn5f42vjhx6h25c7v67n14ymqxn8glqa97d0rajd99y64n4"))))))
+
 (define-public talloc
   (package
     (name "talloc")