This migrates the above files from tempest. This includes tempest commits:
* limits_client.py : Ice3665e91ff34409f6f105303213303d1fca1816
* limits.py : Ica929c402a3d042ae751302384e68853eb28b405
* test_limits_client.py: I3ad6761651cec5e66012d08e6b63322f53286a5c
to see the commit history for these files refer to the above Change-Ids
in the tempest repository
Partially implements blueprint migrate-service-clients-to-tempest-lib
Change-Id: I80c6e148ae30148e591d24675fe068c829a0867a