Fix #21594: converting bevel objects to mesh stops displaying them in spacial cases

Mesh's boundbox should be re-calculated after curve->mesh conversion.
To avoid troubles with displaying texture space i've used
tex_space_mesh() for this.

source/blender/blenkernel/intern/mesh.c

@@ -987,6 +987,9 @@ void nurbs_to_mesh(Object *ob)
 
 	me->totcol= cu->totcol;
 	me->mat= cu->mat;
+
+	tex_space_mesh(me);
+
 	cu->mat= 0;
 	cu->totcol= 0;