ping: Remove an extra new line character

This matches the behavior when an RR truncated route is printed.

Reviewed by: markj
MFC after: 1 week
Pull Request: https://github.com/freebsd/freebsd-src/pull/863
Differential Revision: https://reviews.freebsd.org/D39485

(cherry picked from commit d2c9a140547acf1bfe3a233ef15cf971be93e14d)