Use HTTPRequestV3 instead of HTTPRequest in v3 API tests

This patch uses HTTPRequestV3 instead of HTTPRequest in
v3 API tests and removes the "/v3", it has been specified
already in HTTPRequestV3.

Change-Id: I0b973458b2afac4b3e6eb16e11a56bd301f1b6df
Merge "Use HTTPRequestV3 instead of HTTPRequest in v3 API tests"