r4561: This looks a lot larger than it is, this is to reduce the clutter on future

r4561: This looks a lot larger than it is, this is to reduce the clutter on future
patches.

Pass down the pipe_idx down to all functions in cli_pipe where nt_pipe_fnum is
referenced. First step towards having multiple pipes on a cli_struct. The idea
is to not have a single nt_pipe_fnum but an array for the pipes we support.

Volker
(This used to be commit 93eab050201d4e55096a8820226749f001597b5d)