Compute things in argument order
Only figure out CS endpoint when it's needed

This will make it more obvious how to refactor it later.
Assert delete_server passes lb_response to remove_from_load_balancer
Make that test pass
Minor docstring tweak
Clarify test intent in docstring
Re-use test data
Also throw in an LB response
Fix a number of changes due to using lb response

Note that this was previously using ints as node ids, which it probably
shouldn't have?
RCv3 tests: add_to_load_balancer takes lb_response
Make all the tests pass

Closes #767.
Fix lint
Merge branch 'master' into rcv3-delete
Make docstrings not bogus

Thanks, @cyli!
Merge branch 'rcv3-delete' of github.com:rackerlabs/otter into rcv3-delete
Merge branch 'master' into rcv3-delete
Merge pull request #778 from rackerlabs/rcv3-delete

Stop doing lb_type dispatch in delete_server