cyclades: Update snapshot based on Ganeti job

Make Cyclades update the state of a snapshot in Pithos DB based on
the result of the corresponding Ganeti job. This is required to be
performed by Cyclades, because Pithos has no way to know whether an
unavailable snapshot will ever by completed or not (e.g. the Ganeti
job failed or it still has not completed).

Refs grnet/synnefo#231
cyclades: Reconciliation for stale snapshots

Extend 'reconcile-servers' command to perform reconciliation for
snapshots, which can occur if the Ganeti job failed but the
corresponding message from eventd has never been processed. In order to
make reconciliation possible, Cyclades store a special metadata on the
snapshot that contains the Ganeti ID and the job ID that will create the
snapshot.

Closes grnet/synnefo#231
cyclades: Fix PEP8 issues
burnin: Don't attach two NICs to public networks

Burnin used to attach two NICs to public networks and test that the
virtual machine is accessible through both NICs. This test used to fail
because the virtual machine has only one gateway and the firewall
doesn't allow traffic that comes from one NICs to be routed through the
other.

Remove the above test and instead first detach the virtual machine from
the public network and then re-attach it (hence test hotplugging
functionality).
burnin: Remove temporary created files

Remove temporary files that have been created by the
Pithos TestSuite.
burnin: Update dependency on kamaki version '0.13'

Kamaki version '0.13' has added support for Synnefo projects (moving
resources between projects, allocating resources from a specific project
etc). In order for snf-burnin to test these functionalities, a newer
version of kamaki is needed.