configure.ac: add foreign to AM_INIT_AUTOMAKE

We do not care about the portability warnings implied by the implicit
'gnu' option. Switch to 'foreign' to opt out of checking the files
present in the top directory to let us drop ChangeLog completely.
Signed-off-by: NJán Tomko <jtomko@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

configure.ac

@@ -24,6 +24,7 @@ AH_BOTTOM([#include <config-post.h>])
 AC_CONFIG_MACRO_DIR([m4])
 dnl Make automake keep quiet about wildcards & other GNUmake-isms
 AM_INIT_AUTOMAKE([
+    foreign
     -Wno-portability
     tar-pax
     no-dist-gzip