gnu: Remove duplicate package.

* gnu/packages/autotools.scm (libtool-2.4.7): Remove variable.

gnu/packages/autotools.scm

@@ -519,18 +519,6 @@ (define-public libtool
     (license gpl3+)
     (home-page "https://www.gnu.org/software/libtool/")))
 
-(define-public libtool-2.4.7
-  (package
-    (inherit libtool)
-    (version "2.4.7")
-    (source (origin
-              (method url-fetch)
-              (uri (string-append "mirror://gnu/libtool/libtool-"
-                                  version ".tar.xz"))
-              (sha256
-               (base32
-                "0pb3l4x37k6fj1lwnpzws55gi3pxl0hx56jm4bzmbrkw0mzj2zsg"))))))
-
 (define-public config
   (let ((revision "1")
         (commit "c8ddc8472f8efcadafc1ef53ca1d863415fddd5f"))