Move scoped_ptr "free" functions into the webrtc namespace.
Move scoped_ptr "free" functions into the webrtc namespace.

Resolves a conflict with Chromium's scoped_ptr on the recently added
make_scoped_ptr().

TEST=local Chromium Linux build passes.
R=henrike@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/26969004

git-svn-id: 03ae4fbe531b1eefc9d815f31e49022782c42458@7535 4adac7df-926f-26a2-2b94-8c16560cd09d

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