Add os-aggregates support - #691

Hello @jaypipes, @jtopjian ! Please review this stuff, when you have time :)

Coverage remained the same at 72.921% when pulling b60e167 on ildarsv:add-host-aggregates into 05116c7 on gophercloud:master.

Build succeeded.

• gophercloud-unittest http://logs.openlabtesting.org/logs/91/691/b60e1676c4132752a04083620e5bc1414775935e/check/gophercloud-unittest/f7614df/ : SUCCESS in 1m 10s
• gophercloud-acceptance-test http://logs.openlabtesting.org/logs/91/691/b60e1676c4132752a04083620e5bc1414775935e/check/gophercloud-acceptance-test/68b926e/ : SUCCESS in 20m 28s

@ildarsv Thank you for submitting this. I did a cursory scan and this looks good - thank you for limiting this to only List as well as including documentation.

There are three things missing, though, before I can do a full review:

1. Link to the Nova code that implements aggregates.
2. Unit tests
3. Acceptance test (even if the test returns no actual results)

Please let me know if you have any questions or need any help.

Coverage increased (+0.04%) to 72.96% when pulling 9ddbf1a on ildarsv:add-host-aggregates into 05116c7 on gophercloud:master.

@jtopjian Thanks for the quick response! Sorry for the non-observance of rules.
I've added link to the Nova code and required tests. Please review when you have time.

Build failed.

• gophercloud-unittest http://logs.openlabtesting.org/logs/91/691/9ddbf1a5869a665b475fdd971e39bdf7e07a05d5/check/gophercloud-unittest/89521e2/ : SUCCESS in 1m 18s
• gophercloud-acceptance-test http://logs.openlabtesting.org/logs/91/691/9ddbf1a5869a665b475fdd971e39bdf7e07a05d5/check/gophercloud-acceptance-test/f7103d6/ : POST_FAILURE in 34m 54s

Coverage increased (+0.04%) to 72.96% when pulling 3debc2c on ildarsv:add-host-aggregates into 05116c7 on gophercloud:master.

Build succeeded.

• gophercloud-unittest http://logs.openlabtesting.org/logs/91/691/3debc2c8fac90b14efe72d126b94e5017af6742b/check/gophercloud-unittest/79b56f4/ : SUCCESS in 1m 46s
• gophercloud-acceptance-test http://logs.openlabtesting.org/logs/91/691/3debc2c8fac90b14efe72d126b94e5017af6742b/check/gophercloud-acceptance-test/46605a4/ : SUCCESS in 43m 20s

@ildarsv Thanks!

In general this looks good. I have one item for discussion, though: the list of fields defined here:

https://github.com/openstack/nova/blob/09ed3b5626ac306e59856db89858eb7bee4daa0e/nova/objects/aggregate.py#L242-L250

shows a metadata field. I think we should include this in the results.go file. It should be a simple map[string]string type.

I think it should be safe to leave out the deleted field and the timestamp fields, at least for now. There's a comment in the objects/aggregate.py file that mentions delete and deleted_at being deprecated.

Let me know if you have any questions or see a reason not to include metadata.

@jtopjian Good point, thanks! I've added metadata field. Yes, let's skip the rest fields.

Coverage decreased (-0.1%) to 72.784% when pulling d97bbf0 on ildarsv:add-host-aggregates into 05116c7 on gophercloud:master.

Coverage increased (+0.04%) to 72.784% when pulling 907bb55 on ildarsv:add-host-aggregates into 8e59687 on gophercloud:master.

Build succeeded.

• gophercloud-unittest http://logs.openlabtesting.org/logs/91/691/907bb554d4395f0db0023e5a00b9e3e6bc5013df/check/gophercloud-unittest/67ecfe2/ : SUCCESS in 1m 17s
• gophercloud-acceptance-test http://logs.openlabtesting.org/logs/91/691/907bb554d4395f0db0023e5a00b9e3e6bc5013df/check/gophercloud-acceptance-test/6c4988f/ : SUCCESS in 26m 54s

This looks good to me. Thank you for working on it :)