Revert "Add DCHECK to ensure that NetEq's packet buffer is not empty"
Revert "Add DCHECK to ensure that NetEq's packet buffer is not empty"

This reverts r7719. It failed to compile in Chromium.

TBR=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/30179004

git-svn-id: 03ae4fbe531b1eefc9d815f31e49022782c42458@7720 4adac7df-926f-26a2-2b94-8c16560cd09d

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