Revert "Removed the source type from the log message"

This reverts commit 00da115b31b078283513847f3a02658e18b491ca.

Signed-off-by: Johannes Tuchscherer <jtuchscherer@pivotallabs.com>

Conflicts:
	src/github.com/cloudfoundry/loggregatorlib
	src/loggregator/sinkserver/message_router.go