If a disk image import failed, XenCenter did not release its handle on the directory containing the image.
If a disk image import failed, XenCenter did not release its handle on the directory containing the image.

Signed-off-by: Konstantina Chremmou <a7d1f757a659045fb6db8c1e3849a1c8ad00b97a@citrix.com>

minli1/xenadmin,kc284/xenadmin,minli1/xenadmin,MihaelaStoica/xenadmin,kc284/xenadmin,minli1/xenadmin,MihaelaStoica/xenadmin,xenserver/xenadmin,kc284/xenadmin,MihaelaStoica/xenadmin,minli1/xenadmin,kc284/xenadmin,MihaelaStoica/xenadmin,minli1/xenadmin,minli1/xenadmin,kc284/xenadmin,MihaelaStoica/xenadmin,xenserver/xenadmin,MihaelaStoica/xenadmin,xenserver/xenadmin