gnu: atop: Update source hash.

The new ‘atop-2.9.0.tar.gz’ adds a single file, ‘mkdate’, which, when
available, generates a ‘versdate.h’ file containing the current date.

* gnu/packages/admin.scm (atop): Update source hash and add snippet.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>
Change-Id: I2de2068d052d0b37aff1a6d18f5639baac6ccdfa

gnu/packages/admin.scm

@@ -5122,7 +5122,12 @@ Netgear devices.")
                                   version ".tar.gz"))
               (sha256
                (base32
-                "1y4qmc8i7zg2cqrmz38dxbsj8bb2h7jm1zz23gqcdygkgaymwddw"))))
+                "09prpw20ps6cd8qr63glbcip3jrvnnic0m7j1q02g8hjnw8z50ld"))
+              (snippet
+               ;; The 'mkdate' script generates a new 'versdate.h' header
+               ;; containing the build date.  That makes builds
+               ;; non-reproducible so remove it.
+               #~(delete-file "mkdate"))))
     (build-system gnu-build-system)
     (arguments
      (list