meson: drop remaining bits from Makefile.am

meson: drop remaining bits from Makefile.am

There is no alternative to DISTCHECK_CONFIGURE_FLAGS in Meson. We could
enable -Werror unconditionally but that would affect all users. It is
mainly used in our CI environment so we can run meson with --werror to
enable it in configure time which will be picked up by meson dist as
well.

XZ_OPT is not relevant with meson since it uses shutil.make_archive
which uses lzma python module to do the compression.

Introducing rpm and srpm rules should be possible with Meson but we
don't even use them in our CI and it's easy to run 'ninja dist'
followed by rpmbuild manually.

As for the ci rules that is simply not possible in the same way, we
would have to have a lot of aliases for all the ci rules and that would
be just insane.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Neal Gompa <ngompa13@gmail.com>