Correct credentials not being used.

[nuwang]

This error was encountered by Jessica when trying to launch with both saved and temp credentials. Strangely, the keypairs were fetched, but the vm_types always error out.

She had 2 set of credentials saved with none set as default. Using temp credentials also did not help.

Could be related to: #115

Setting one set of credentials as default solved the problem. This seems incorrect, since it should always respect selected credentials or temp credentials.

Logs revealed following:

ERROR:django.request:Internal Server Error: /cloudlaunch/api/v1/infrastructure/clouds/nectar/regions/melbourne/zones/melbourne-qh2-uom/compute/vm_types/
Traceback (most recent call last):
  File "/app/venv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/app/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/app/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/app/venv/lib/python3.6/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/app/venv/lib/python3.6/site-packages/rest_framework/viewsets.py", line 114, in view
    return self.dispatch(request, *args, **kwargs)
  File "/app/venv/lib/python3.6/site-packages/rest_framework/views.py", line 505, in dispatch
    response = self.handle_exception(exc)
  File "/app/venv/lib/python3.6/site-packages/rest_framework/views.py", line 465, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/app/venv/lib/python3.6/site-packages/rest_framework/views.py", line 476, in raise_uncaught_exception
    raise exc
  File "/app/venv/lib/python3.6/site-packages/rest_framework/views.py", line 502, in dispatch
    response = handler(request, *args, **kwargs)
  File "/app/venv/lib/python3.6/site-packages/rest_framework/mixins.py", line 38, in list
    queryset = self.filter_queryset(self.get_queryset())
  File "/app/venv/lib/python3.6/site-packages/djcloudbridge/drf_helpers.py", line 34, in get_queryset
    return self.list_objects()
  File "/app/venv/lib/python3.6/site-packages/djcloudbridge/views.py", line 343, in list_objects
    provider = view_helpers.get_cloud_provider(self)
  File "/app/venv/lib/python3.6/site-packages/djcloudbridge/view_helpers.py", line 19, in get_cloud_provider
    request_creds = get_credentials(cloud, view.request)
  File "/app/venv/lib/python3.6/site-packages/djcloudbridge/view_helpers.py", line 33, in get_credentials
    return get_credentials_from_profile(cloud, request)
  File "/app/venv/lib/python3.6/site-packages/djcloudbridge/view_helpers.py", line 231, in get_credentials_from_profile
    raise ValueError("Too many credentials to choose from.")
ValueError: Too many credentials to choose from.