peer_{de,at}tach were called from inside assert().
We don't support building without NDEBUG but it's not tidy.
Rearrange to attach peer outside assert calls.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>