Changed linear filter error window in AEC3 to Hanning
Changed linear filter error window in AEC3 to Hanning

Changing window type which improves the filter accuracy
at the cost of a slight reduction in convergence time.

Bug: webrtc:8661
Change-Id: Id0e5c66ec179f94471cbca0a2b8d1b94d8146ca6
Reviewed-on: https://webrtc-review.googlesource.com/34501
Commit-Queue: Per Åhgren <3616c2c8a2c30a769c5419f89b4a810ea6e2f079@webrtc.org>
Reviewed-by: Gustaf Ullberg <3619ad972adf2eeb42172b0d9b4d612d59d226c7@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#21347}
TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc