Update JsonCPP dependency + owners

This patch updates our third_party jsoncpp dependency from an old
version circa 2012, to latest head from the GitHub repository. As part
of this update, the overrides + patches are no longer necessary and are
being deleted. As well, the OWNERS file has been updated to a new owner
(me).

Change-Id: I58ee01788b00f0b25e9a2341589189023621965e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1674449
Commit-Queue: Jordan Bayles <jophba@chromium.org>
Reviewed-by: Sam Clegg <sbc@chromium.org>
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Auto-Submit: Jordan Bayles <jophba@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676681}
10 files changed