Include "fuchsia" as a known "deps_os" value
Include "fuchsia" as a known "deps_os" value

This fixes an issue where "--deps=all" syncs everything but fuchsia.

R=machenbach@chromium.org, a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org, a947adef8e572dca259bba92af2d4319f496cd4c@chromium.org

Bug: 848676
Change-Id: I782184b615968140d0e9a0146169fa12a9ebe0c5
Reviewed-on: https://chromium-review.googlesource.com/1084211
Reviewed-by: Wez <a947adef8e572dca259bba92af2d4319f496cd4c@chromium.org>
Reviewed-by: Andrii Shyshkalov <a30c74fa30536fe7ea81ed6dec202e35e149e1fd@chromium.org>
Commit-Queue: Sergiy Byelozyorov <aadb4a11584aa9878242ea5d9e4b7e3429654579@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools