hdf5_msb

Let catch_out_err_and_rc() callers redirect the standard input and
output streams using STDIN_PATH and STDOUT_PATH.  I will use that for
the zoo reader and writer.  Move redirection of standard error output to
the standard output stream outside of the curly braces, since usually
I want to save the `echo` and `wait` output, too, and it makes the
redirection of the supervised program a little easier to follow, I
think.