Fixes #3457 - Prevent /etc/init.d/rudder-agent to display error when pid files are empty
Refs #3457 - Fix ambiguous comments
Refs #3457 - Fix indentations
Merge pull request #44 from nperron/3457/dev/prevent_agent_to_have_error_when_pidfiles_are_empty

Fixes #3457 - Prevent /etc/init.d/rudder-agent to display error when pid files are empty