CA-212079: Allow XenMotion and AD during RPU from pre-Dundee

[robhoes]

I have tested this by removing the restrict_xen_motion key from the license_params of the slave in a two-host pool. It used to be restrict_xen_motion = "false", i.e. XenMotion is enabled, on both the master and slave. Then I checked the resulting value of pool.restrictions. Before the patch, pool.restrictions had restrict_xen_motion = "true" (i.e. XenMotion disabled). With the patch, it correctly had restrict_xen_motion = "false".

[lindig]

I wonder: wouldn't it be simpler to express feature sets using string sets (Set.Make(String))?

[robhoes]

@lindig Using a Set may work, but then based on the feature type. I'm not sure if that's going to be a lot simpler than what we have now, based on lists, because duplicates are not really a problem. Also, changing the types was really a step further than I wanted to go in this bugfix.

[lindig]

One comment about names;

• compute_pool_restrictions
• find_additional_flags
• compute_additional_restrictions

These names suggest actions (compute, find) but represent property lists. I would have used names that focus on these properties: common_features, extra_features, extra_restrictions or similar. No need to change them, though.

[robhoes]

We talked about the names above, and seem to have to accept that different styles which can all be justified in some manner :)

I did update the first patch to better explain the terminology in a comment on top of the file.

[lindig]