README: Reword deploy+destroy for BOSH+CF
README: Reword deploy+destroy for BOSH+CF

To indicate that you need to setup the pipeline and then run it. As
suggested in Pivotal, I might refactor the pipeline deploy scripts together,
but that'll come in a separate PR.

jimconner/paas-cf,alphagov/paas-cf,jimconner/paas-cf,jimconner/paas-cf,alphagov/paas-cf,alphagov/paas-cf,alphagov/paas-cf,jimconner/paas-cf,jimconner/paas-cf,alphagov/paas-cf,alphagov/paas-cf,jimconner/paas-cf,alphagov/paas-cf,alphagov/paas-cf,jimconner/paas-cf