storage: Set ret = -1 on failures in virStorageBackendUpdateVolTargetInfo
storage: Set ret = -1 on failures in virStorageBackendUpdateVolTargetInfo

While processing the volume for lseek, virFileReadHeaderFD, and
virStorageFileGetMetadataFromBuf - failure would cause an error,
but ret would not be set. That would result in an error message being
sent, but successful status being returned.

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