[fuel-agent] artifact utils target must check if given filename is a block device and exists

[Alexander Gordeev]

This following piece of code:
https://github.com/stackforge/fuel-agent/blob/master/fuel_agent/utils/artifact.py#L51-L63

will silently create new file if it doesn't exist and won't throw any error for that case.

it should check at least: that existing file is a block device. Otherwise, an exception must be raised.

[Dmitry Pyzhov (dpyzhov)]

Review is here: https://review.openstack.org/#/c/228503/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/228503
Committed: https://git.openstack.org/cgit/stackforge/fuel-agent/commit/?id=b2050bd4ee6b8c8b497a8ef89d4b5262a06f09ec
Submitter: Jenkins
Branch: master

commit b2050bd4ee6b8c8b497a8ef89d4b5262a06f09ec
Author: Andrey Tykhonov <email address hidden>
Date: Mon Sep 28 18:39:44 2015 +0300

    Check whether given filename is a special device

    Accept only a special device file, otherwise throw an exception.

    Change-Id: I23598b52d273091a877896968d17377373322cae
    Closes-bug: #1492989

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/233580

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/233580
Committed: https://git.openstack.org/cgit/stackforge/fuel-agent/commit/?id=29818cf4c1e5cf086f433b222a5055fed686d104
Submitter: Jenkins
Branch: master

commit 29818cf4c1e5cf086f433b222a5055fed686d104
Author: Andrey Tykhonov <email address hidden>
Date: Mon Oct 12 13:59:49 2015 +0300

    Check whether given filename is a special device

    Accept only a special device file, otherwise throw an exception.

    Change-Id: Ib91aaba64be2c338845d66b819f0125a586131a4
    Closes-bug: #1492989