The checks for reserved names are spread far and wide. Move one from
add_name() to new check_defn_name_str(). This is a first step towards
collecting them all in dedicated name checking functions next to
check_name().
While there, drop the quotes around the meta-type in
check_name_str()'s error messages: "'command' uses ... name 'NAME'"
becomes "command uses ... name 'NAME'".
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190927134639.4284-13-armbru@redhat.com>