Silence deprecation warning for av_lockmgr_register
Silence deprecation warning for av_lockmgr_register

It should not be used anymore - see
https://webrtc-review.googlesource.com/39503
but it can be removed only after the DEPS roll.

Bug: webrtc:8745
Change-Id: I1ee29948e99be6cb4a700b67d37f72a0747a9fc5
Reviewed-on: https://webrtc-review.googlesource.com/39505
Reviewed-by: Patrik Höglund <b486136ee68458b09c92c86c39f451c87d6ef6a1@webrtc.org>
Commit-Queue: Oleh Prypin <5baa3e04f9bd6ba7a2a4b56625a3c84f19237cdb@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#21612}
ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc