Modify oauth calls to expect urlencoded responses

Previously, the server side would send jsonwrapped urlencoded
responses. Now we are removing the jsonwrapped portion so that
the responses for oauth calls are just urlencoded.

Related-Bug: #1336910
Change-Id: I0431a581a5c3fca38e22751ef9bde034f0a89a30
Merge "Modify oauth calls to expect urlencoded responses"