bug#17032: side effect bug...

[Roméo Capulet]

The option "-n" have a side effect with the option "-P" and the regexp 
'^\r$', the line numbers got overwritten by the carriage return char so 
these don't appear on output.

cmd ex: grep -Pn '^\r$' file.txt

ps: I know I can see the numbers by redirecting output in a file.