Move the singleton to a common location

Looks like it will be used by many other componts as well.

Change-Id: I2ac2b879db461d3fc9e70de84880a7e9b34076df
Proposed EC2 OpenStack extension

'PAUSED' OS instance status is not mappable to any EC2 status correctly.
Adding a 'paused' status seams to the only viable way to handle this.

Normally you cannot reach this status just with the EC2 API, but all other
defined EC2 statuses are schematically incorrect for status mapping.

A suspend can be considered as a 'stopped' status.
'rebooting' can be considered as 'pending' status.

Using the 'paused' status is only valid when the VM paused because
of the user's explicit request, so it is not temporary pause because
of an internal operation sequence. If the nova just pauses the VM
just temporary it must report 'pending' (or 'running' ) status.

Change-Id: Id4500dd6e38e078d0b0b76fb0dd6a81c054ef646
Merge "Proposed EC2 OpenStack extension"
Merge "Move the singleton to a common location"