storage: Move virStorageBackendDiskDeleteVol
storage: Move virStorageBackendDiskDeleteVol

Move the API to before virStorageBackendDiskCreateVol in order to be
able to call the DeleteVol API when virStorageBackendDiskReadPartitions
fails so that we don't by chance leave a partition on the disk.

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