Fix agent_id with string type in API samples files for os-agents v2

The agent_id should be integer for agent create and index. But in
the api sample file it is string type. It's because the api sample
tests provide agent_id with string type in fake data. This patch
correct the api sample files and tests.

For agent update, it use agent_id that passed from url, make the
response use string for agent_id. We can't fix this problem for
back-compatibility. This will be fix in the future after v3 API
expose by micro-version

Change-Id: I262b4b26c94dba003e80bda2f38d2e985ef9f220
Partial-Bug: #1333494
Revert "Sync revert and finish resize on instance.uuid"

This reverts commit d27987fa56156392c06b1185b44e36dc9720435c which
actually seems to have retriggered the issue it was designed to fix.

Related-Bug: #1326778

Change-Id: Ia1905177de8494f9c3abb3bcfa0866c7bcb33f93
Merge "Revert "Sync revert and finish resize on instance.uuid""
Merge "Fix agent_id with string type in API samples files for os-agents v2"