remove unicode casting for syslog line, fixes #804

Causes a syslog emergency broadcast message to be displayed in certain
circumstances, like when using Python 2.6.5 on CentOS 5.x.

Since hostnames in unicode aren't valid, and we don't currently support
unicode host tags, this should be safe to remove.
Merge pull request #804 from DataDog/804_logging

Agent startup broadcasts 'emergency' message on RPM-based system