Make OAuth testcase use actual request headers
Make OAuth testcase use actual request headers

OAuth test verifies that access_token manager's methods make requests with
certain parameters. It is supposed to use values from mocked http handler
and compare them with referential values acquired from oauth client.

But instead of using values from mocked handler, it used the values from
oauth client and compared them with values from the client acquired using
attributes, basically testing oauthlib and not access_token manager's
methods.

Make the test compare correct values and remove check of timestamp,
which was useless because it is always mocked in tests and not provided in
actual requests.

As a consequence, use of get_oauth_params, which changed in oauthlib
1.0 and blocked the gate, was removed.

Closes-Bug: 1477177
Closes-Bug: 1477247
Change-Id: I5e049163f84fde5827104fd4a6441222eb08468f
(cherry picked from commit 7d5d8b343232ee5faf4de3381024095619335929)

darren-wang/ksc,darren-wang/ksc