packaging/ovirt-hosted-engine-setup: avoid host name collision.

Signed-off-by: Zhao Chao <zhaochao1984@gmail.com>
packaging/ovirt-hosted-engine-setup: update SPEC file.

Signed-off-by: Zhao Chao <zhaochao1984@gmail.com>
iso-building: add a script for downloading new appliances and
              clean testing directory (keep the 3 latest ones).

Signed-off-by: Zhao Chao <zhaochao1984@gmail.com>