crushtool: consolidate_whitespace() should eat everything except \n

CRUSH map source with \r (like a DOS text file) failed to compile
with the usual nonuseful message; turns out that eating \r along with
' ' and '\t' etc. solves that problem.

Fixes: #3834
Signed-off-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
crushtool: warn usefully about missing output spec

When running with --test, you must request output to CSV files or
specific types of output to --show-X; make the error message
clarify what the tool wants.

Fixes: #3827
Signed-off-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>