gnu: di: Update to 4.51.

* gnu/packages/admin.scm (di): Update to 4.51.
[arguments]: Don't explicitly return #t from phases.

gnu/packages/admin.scm

@@ -3205,13 +3205,13 @@ (define-public thefuck
 (define-public di
   (package
     (name "di")
-    (version "4.50")
+    (version "4.51")
     (source
      (origin
        (method url-fetch)
        (uri (string-append "mirror://sourceforge/diskinfo-di/di-" version ".tar.gz"))
        (sha256
-        (base32 "0aj9ldkvmj8fmrk685vd2gagz0q8lwsn2nfbx6r6mza94mn8pw42"))))
+        (base32 "1fv12j9b9sw6p38lcbzcw87zl5qp1aa7a4a4jn3449zz9af15ckr"))))
     (build-system gnu-build-system)
     (arguments
      `(#:tests? #f                      ; obscure test failures
@@ -3221,8 +3221,7 @@ (define-public di
          (add-before 'build 'setup-environment
            (lambda* (#:key outputs #:allow-other-keys)
              (setenv "CC" ,(cc-for-target))
-             (setenv "prefix" (assoc-ref outputs "out"))
-             #t)))
+             (setenv "prefix" (assoc-ref outputs "out")))))
        #:make-flags (list "--environment-overrides")))
     (home-page "https://gentoo.com/di/")
     (synopsis "Advanced df like disk information utility")