Fix ::~LogMessage to print as a string.
Fix ::~LogMessage to print as a string.

R=andrew@webrtc.org
BUG=

Review URL: https://webrtc-codereview.appspot.com/26949004

git-svn-id: 03ae4fbe531b1eefc9d815f31e49022782c42458@7525 4adac7df-926f-26a2-2b94-8c16560cd09d

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