#69 evms segfault at lvm_volumes.c:437 in case of broken LVMG

[Gleb Stiblo]

I have broken LVMG. And some
lv_number`s(pe_map[j].pe.lv_num) are greate than MAX_LV
in it. So group->volume_list[lv_number] point to wrong
place and using it cause segfault.

Check lv_number correctness need to be added here(may
be not only here).