Allow aggregate create to have None as the az

Aggregates do not require a zone any more, but in order to keep the current API,
Allow for availibilty zone to be set to None.

Fixes bug 1123468

Change-Id: I5209311f3417b5d7cdf343e5c06104357ed523d5
Canonizes IPv6 before insert it into the db

This is normalize IPv6 to be inserted always in shortened and no mixed form
into db, this way postgresql, which uses INET type, and other databases like
mysql will have equivalent contents.

Fix bug 1116236
Related to bp migration-testing-with-data

Change-Id: Iae5aa8a28e3ccc0d3a1a96459232b827c3a19d5c
Merge "Allow aggregate create to have None as the az"
Merge "Canonizes IPv6 before insert it into the db"