Sync download_tools.py with changes in gclient_utils module.
Sync download_tools.py with changes in gclient_utils module.

Bug: none
Change-Id: I3eb0d995527742245639ea7f9bc59113184ea428
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/147861
Reviewed-by: Oleh Prypin <5baa3e04f9bd6ba7a2a4b56625a3c84f19237cdb@webrtc.org>
Commit-Queue: Sergey Silkin <fc631354f276613a5410ea259cf4618b2846d39b@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#28742}

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