storage: dir: adapts .wipeVol for ploop volumes
storage: dir: adapts .wipeVol for ploop volumes

The modification of .volWipe callback wipes ploop volume using one of
given wiping algorithm: dod, nnsa, etc.
However, in case of ploop volume we need to reinitialize root.hds and DiskDescriptor.xml.

v2:
- added check on ploop tools presens
- virCommandAddArgFormat changed to virCommandAddArg

Signed-off-by: Olga Krishtal <6ab40c8ce88e23ce184acbfdab82214e3fc33e97@virtuozzo.com>

crobinso/libvirt,zippy2/libvirt,fabianfreyer/libvirt,eskultety/libvirt,jfehlig/libvirt,eskultety/libvirt,nertpinx/libvirt,jardasgit/libvirt,eskultety/libvirt,VenkatDatta/libvirt,libvirt/libvirt,fabianfreyer/libvirt,datto/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,zippy2/libvirt,datto/libvirt,jardasgit/libvirt,datto/libvirt,eskultety/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jfehlig/libvirt,olafhering/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,zippy2/libvirt,libvirt/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,taget/libvirt,crobinso/libvirt,libvirt/libvirt,datto/libvirt,taget/libvirt,andreabolognani/libvirt,jfehlig/libvirt,andreabolognani/libvirt,zippy2/libvirt,datto/libvirt,libvirt/libvirt,taget/libvirt,taget/libvirt,VenkatDatta/libvirt,crobinso/libvirt,olafhering/libvirt,crobinso/libvirt,VenkatDatta/libvirt,olafhering/libvirt,jardasgit/libvirt,nertpinx/libvirt,jfehlig/libvirt,nertpinx/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,eskultety/libvirt,taget/libvirt,olafhering/libvirt,nertpinx/libvirt