Add support microversion 2.75 which implement
multiple API cleanup changes.
1. Making server representation always consistent among all APIs
returning the complete server representation.
- Test cases added.
2. Change the default return value of ``swap`` field from the empty string
to 0 (integer) in flavor APIs.
- Test cases added.
Nova side path: https://review.opendev.org/#/c/666889/
Change-Id: Iec2cfc629dffd53178ef88a31fcd16a3f32e2e27
Partial-Implements: blueprint api-consistency-cleanup