Fix usage of rest_client expected_success() in tests

rest_client expected_success() method expect read_code
must be int and states the same in doc string .

Tempest is converting that to error instead of false pass.
Details: I3f4c58bdbb172805514831103927d3464d65d7f3

Baremetal tests are still needed and running for Ironic stable branches
so need to fix these.

Change-Id: I31f90dc69c36368ce12ccfe93ed477f7d818ef6c
1 file changed