Remove duplicate entries from AUTHORS file
Remove duplicate entries from AUTHORS file

BUG=none
NOTRY=True
TBR=alessiob@webrtc.org

Review-Url: https://codereview.webrtc.org/2813553004
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#17617}

TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc