Make resize server schema 'additionalProperties' False

Nova V2.1 API has strong input validation by making validation
through JSON schema.

This patch makes resize server schema 'additionalProperties' to False
as all resize server extensions are implemented in V2.1.
After this, V2.1 will not allow extra arg for resize server.

This patch also adds some unit tests for those cases.

Partially implements blueprint v2-on-v3-api

Change-Id: Ie150906b85f9059d4828e1b597890b6c234867a9
Merge "Make resize server schema 'additionalProperties' False"