engine: remove handling GetStorageDomainListError after getImagesList

getImagesList API used by GetImagesListCommand can't return
GetStorageDomainListError therefore special handling of this error
is removed.

Change-Id: I56d639d83bd24e6b3939933998d17c5498670b5a
Signed-off-by: Sergey Gotliv <sgotliv@redhat.com>
engine: Remove calls to getImageDomainsList API

This API is deprecated in VDSM. Use getImagesList instead.

Change-Id: I33069871db34e8b129c4d80098523654cd2a0629
Signed-off-by: Sergey Gotliv <sgotliv@redhat.com>