The response being passed to _extract_error_json
is assumed to be a requests.Response but can also
be a http.client.HTTPResponse.
This patch adds a try statement where it first tries
for a requests.Response and if not set falls back on
parsing the string body instead of trying to use the
json() helper function in requests.Response.
Change-Id: I61840d284b5d3a249f621822b277c9bd6825140d
Closes-Bug: 1870264
c024b4fc43