init: obsolete usages of AM_INIT_AUTOMAKE not supported anymore

init: obsolete usages of AM_INIT_AUTOMAKE not supported anymore

This is a follow-up on commit v1.12-66-g27136df of 2012-05-06, "init: warn
against obsolete usage of AM_INIT_AUTOMAKE".

With this change, we drop support for the two-arguments and three-arguments
invocation forms of the AM_INIT_AUTOMAKE macro, as in either of:
    AM_INIT_AUTOMAKE($PACKAGE, $VERSION)
    AM_INIT_AUTOMAKE($PACKAGE, $VERSION, NODEFINE)

* NEWS, doc/automake.texi: Update.
* m4/init.m4 (AM_INIT_AUTOMAKE): Report the two- and three-arguments
invocation form as a hard error.
* t/aminit-moreargs-deprecation.sh: Renamed ...
* t/aminit-moreargs-deprecation.sh: ... to this, and updated to check
the new semantics.
* t/ac-output-old.tap: Adjust by avoiding old-style uses of AC_INIT
and AM_INIT_AUTOMAKE.
* t/acsilent.sh: Likewise.
* t/dirlist.sh: Likewise.
* t/dirlist2.sh: Likewise.
* t/req.sh: Likewise.
* t/nodef.sh: Remove as obsolete.
* t/version.sh: Likewise.
* t/version2.sh: Likewise.
* t/backcompat.sh: Likewise.
* t/backcompat2.sh: Likewise.
* t/backcompat3.sh: Likewise.
* t/backcompat5.sh: Likewise.
* t/backcompat4.sh: Renamed ...
* t/backcompat-acout.sh: ... to this.
* t/list-of-tests.mk: Adjust.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>