Fix oslinfo output for arrays.

When outputting default parameter values for aggregates (like colors),
oslinfo nicely output lines like:

  color MyParam [ 0 1 2 ]

But for *arrays*, it strangely put newlines between every element:

  float[4] MyArray 0
  1
  2
  3

This patch makes arrays output on one line, and with bracket notation,
just like aggregates.