* upgrade Rally dependency to point to require 4.1.0
This brings SQLAlchemy 2 support which is covered by
unittests/functional tests now.
* dropping testtools test dep.
We are dropping it just because standard unittest
lib is good enough for our use
* deprecatng murani, sahara, senlin plugins as those projects are
retired
Change-Id: I8ff6f8f8497907091a91c16a2e4a76051827397d