Improve test coverage for fuel_agent

* should be 100%
* also comes with fixups
Partially implements: blueprint image-based-provisioning

Change-Id: I73ff92f65c0872ad82917d22900c3f410986629d
Upgrades, fixed host system upgrader

Switch /etc/fuel/version.yaml to new
version when run host system upgrade
engine because puppet relies on this
file.

This change fixes the bug, when user
runs upgrade several times and puppet
overwrites supervisor configs for
previous version.

Change-Id: I79ff27bb5078d0cf885612af0560b9e1623c6206
Closes-bug: #1349286
allow RadosGW and Ceph/RBD for Glance with vCenter

Only Ceph storage backends for Cinder and Nova should be disabled when
vCenter is used as the hypervisor, Ceph can still be used as storage
backend for Glance and for Swift/S3 object storage.

Change-Id: I5b77ad0a98673e331a5c3e5e7652c30ae2a96354
Closes-Bug: #1316377
Merge "allow RadosGW and Ceph/RBD for Glance with vCenter"
Merge "Upgrades, fixed host system upgrader"
Merge "Improve test coverage for fuel_agent"
Handle exception in agent when node was removed and rediscovered

Change-Id: Icb9bb4282d00b83de44477f9063292a76c444c4c
Closes-Bug: #1349815