midpoint random displacement should not alter the extremities of the edge

bmo_subdivide.c.diff

336,339c336,337
<       if (!params->use_fractal) {
<           alter_co(v1, &e_tmp, params, 0, &v1_tmp, &v2_tmp);
<           alter_co(v2, &e_tmp, params, 1.0, &v1_tmp, &v2_tmp);
<       }
---
>       alter_co(v1, &e_tmp, params, 0, &v1_tmp, &v2_tmp);
>       alter_co(v2, &e_tmp, params, 1.0, &v1_tmp, &v2_tmp);