CBQE-2239: remove paramiko from task module

Should be able to use RemoteMachineShellConnection for most commands

Change-Id: Ie388a914981d89e32a887a0e5949cb7f9e38923f
Reviewed-on: http://review.couchbase.org/37119
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>