Revert "(#5246) Puppetd does not remove it's pidfile when it exits"

This reverts commit e0e31d571f38a3f0436e43ea6662f6d6c1e525c5.

This commit caused spurious error messages when running puppet agent -t if
the agent was also running daemonized (#12188). It would display an error of
unable to remove pidfile, but the error would not affect the exit code.