Do not purge on an non-live workspace

Problem/Motivation

I am working on a client site that use workspaces extensively for content publishing, with multiple editors working on their own site section in their own workspaces. Sometimes a single editor works on multiple workspaces. Each content publish in a workspace triggers a CDN cache clear (Akamai in our case).
Since, the content was not changed (published) in a Live workspace, it stays the same for anonymous user, making the purge unnecessary.

Steps to reproduce

• Enable the workspaces module.
• Add a new workspace and switch to it.
• Edit some content.
• Check the purge queue (you can do it by comparing the count from the purge_queue database table).

Expected result: No purge queue entries should be created.

Actual result: Purge entries are created.

Proposed resolution

Do not add entries to the purge queue if they are changed in a non-Live workspace.

Remaining tasks

Review

User interface changes

None

API changes

None

Data model changes

None