Change Ia89eeb6725459c35369e8f790f68ad9180bd3aba added new
microversion 2.57. This microversion removed field 'personality'
from create server request. By default Nova functional api tests use
samples from '/servers' directory to create a server. But now such
requests got 400 Bad Request because of additional 'personality' field.
We must handle this case if we are testing microversions >= 2.57.
This patch will add sample for microversion 2.57+
Change-Id: I8c4e8ffc00ab53f07e7364767f4480abebd2e357