fix the wait_until examples

[ipl31]

Overview

The example usage of wait_until() w/parameter succeed_on_found=True are incorrect to the best of my understanding.

When using the examples in this file I came across an issue deleting subnets. Specifically my wait_until() calls would throw exceptions because of a 404 even though I had the succeed_on_not_found parameter set to True. After some help from @arthall (thanks Art!) I determined that the examples in this file are incorrect and will reliably error out when trying to use them.

I believe the issue is the wait_until() call is unable to get a response object from the client.get() call when a non-tombstoning resource is deleted and disappears (resulting in 404) before it can get a response object to use for it's property check.

Proposed Fix

The proposed fix does a GET on the resource before calling wait_until() and then passes the resulting response to the wait_until() method. I have tested this fix locally a few times.

Reproduction steps

1. Set your compartment ID and ADs in wait_for_resource_in_state.py.
2. Run wait_for_resource_in_state.py. It should fail on the subnet deletion steps in at least one out of few runs but it will probably fail on all of them.

I get the following type of errors reliably:

Traceback (most recent call last):
  File "wait_for_resource_in_state_ken.py", line 105, in <module>
    oci.wait_until(virtual_network_client, virtual_network_client.get_subnet(subnet_ocid), 'lifecycle_state', 'TERMINATED', succeed_on_not_found=True)
  File "/Users/kcaruso/.virtualenvs/oci/lib/python2.7/site-packages/oci/core/virtual_network_client.py", line 5064, in get_subnet
    response_type="Subnet")
  File "/Users/kcaruso/.virtualenvs/oci/lib/python2.7/site-packages/oci/base_client.py", line 209, in call_api
    return self.request(request)
  File "/Users/kcaruso/.virtualenvs/oci/lib/python2.7/site-packages/oci/base_client.py", line 323, in request
    self.raise_service_error(request, response)
  File "/Users/kcaruso/.virtualenvs/oci/lib/python2.7/site-packages/oci/base_client.py", line 491, in raise_service_error
    original_request=request)
oci.exceptions.ServiceError: {'status': 404, 'message': u'Either Subnet with ID ocid1.subnet.oc1.phx.aaaaaaaanuauphx4dv7ltvdhion36oksvpbjlve54r7fojiuisopl6kflkkq does not exist or you are not authorized to access it.', 'code': u'NotAuthorizedOrNotFound', 'opc-request-id': 'A83957A1AA1645BBAEDB253A48D43A6A/2F91FFDE243B23F7668B8BF2CF3821FF/C9D75A6AC4D5412095DF8AF1D5B430A3'}

[arthall]

Thanks for updating the example, @ipl31.