qemu-options: replace constant 1 with HAS_ARG

This is the only instance of a non-zero constant not using a symbolic
constant.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20200204165638.25051-1-jsnow@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
1 file changed