Fix H404/405 violations for api tests(1/3)

There is a lot of H404/405 violations in Tempest now, and that leads
difficult to migrate the code to tempest-lib or the other projects'
repos. This patch fixes these violations for api tests except compute
and network.

Change-Id: I783862867732b76d836153bf9ef18fb4a5ec6c6e
27 files changed