Remove unused kPowTableFrac which causes anroid clang build failure.
Remove unused kPowTableFrac which causes anroid clang build failure.

http://build.chromium.org/p/tryserver.chromium/builders/android_clang_dbg/builds/84322/steps/compile/logs/stdio

R=niklas.enbom@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2417004

git-svn-id: 917f5d3ca488f358c4d40eaec14422cf392ccec9@4981 4adac7df-926f-26a2-2b94-8c16560cd09d

mwgoldsmith/libilbc,mwgoldsmith/ilbc,TimothyGu/libilbc,mwgoldsmith/libilbc,mwgoldsmith/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,mwgoldsmith/ilbc,mwgoldsmith/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,mwgoldsmith/ilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,mwgoldsmith/ilbc