make-bootstrap: Adjust copied linux headers.

* guix/build/make-bootstrap.scm (copy-linux-headers): Remove header
file 'a.out.h' is no longer part of the linux kernel headers.

guix/build/make-bootstrap.scm

@@ -47,7 +47,6 @@ (define (copy-linux-headers output kernel-headers)
                 (install-file (pk 'src (string-append kernel-headers "/include/linux/" file))
                               (pk 'dest (string-append incdir "/linux"))))
               '(
-                "a.out.h"               ; for 2.2.5
                 "atalk.h"               ; for 2.2.5
                 "errno.h"
                 "falloc.h"