This adds support for the 2.50 microversion which does the following:
* Adds the server_groups and server_groups_members resources to the output
for the 'nova quota-class-show' and 'nova quota-class-update' CLIs.
* Removes the ability to show or update network-related resource quota class
values, specifically floating_ips, fixed_ips, security_groups and
security_group_members.
* Defines explicit kwargs for the update() method in the python API binding.
This also fixes a problem where the 'nova quota-class-update' CLI was
incorrectly capped at the 2.35 microversion for updating network-related
resources. That was true for the os-quota-sets API which is tenant-specific,
but not for the os-quota-class-sets API which is global.
Functional tests are added for the 2.1 and 2.50 microversion behavior for
both commands.
Part of blueprint fix-quota-classes-api
Change-Id: I2531f9094d92e1b9ed36ab03bc43ae1be5290790
5bfa57a433