It is pointless to keep qapi/ object separate from the other
common-objects. Drop the comment.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200118140619.26333-5-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>