Fix scheduler-hints example

The API samples of scheduler-hints contains "hypervisor" and "near"
attributes, but the attributes do not exist in the scheduler-hints
parameter of "create a server" API. This patch changes them to the
existing "same_host" attribute.

Change-Id: Ia6b34fe5b0327b4499df0e0dac623eb42fb07285
Closes-Bug: #1285456
Merge "Fix scheduler-hints example"