gnu: libgcrypt: Integrate grafted update.

* gnu/packages/gnupg.scm (libgcrypt): Update to 1.7.8.
[replacement]: Remove field.
(libgcrypt-1.7.8): Remove variable.
(libgcrypt-1.5)[replacement]: Remove field.

gnu/packages/gnupg.scm

@@ -82,15 +82,14 @@ Daemon and possibly more in the future.")
 (define-public libgcrypt
   (package
     (name "libgcrypt")
-    (replacement libgcrypt-1.7.8)
+    (version "1.7.8")
-    (version "1.7.7")
     (source (origin
              (method url-fetch)
              (uri (string-append "mirror://gnupg/libgcrypt/libgcrypt-"
                                  version ".tar.bz2"))
              (sha256
               (base32
-               "16ndaj93asw122mwjz172x2ilpm03w1yp5mqcrp3xslk0yx5xf5r"))))
+               "16f1rsv4y4w2pk1il2jbcqggsb6mrlfva5vayd205fp68zm7d0ll"))))
     (build-system gnu-build-system)
     (propagated-inputs
      `(("libgpg-error-host" ,libgpg-error)))
@@ -116,22 +115,8 @@ generation.")
     (properties '((ftp-server . "ftp.gnupg.org")
                   (ftp-directory . "/gcrypt/libgcrypt")))))
 
-(define libgcrypt-1.7.8
-  (package
-    (inherit libgcrypt)
-    (replacement #f)
-    (version "1.7.8")
-    (source (origin
-             (method url-fetch)
-             (uri (string-append "mirror://gnupg/libgcrypt/libgcrypt-"
-                                 version ".tar.bz2"))
-             (sha256
-              (base32
-               "16f1rsv4y4w2pk1il2jbcqggsb6mrlfva5vayd205fp68zm7d0ll"))))))
-
 (define-public libgcrypt-1.5
   (package (inherit libgcrypt)
-    (replacement #f)
     (version "1.5.6")
     (source
      (origin