Revert "Add namespace sandbox to about page."
Reason for revert:
See crbug/456993.
This reverts commit 1ef7ee1ee899087d8632a4f905a3a11697a20b81.
TBR=jln,jhawkins,nasko,mdempsky
BUG=456993
Original issue's description:
> Add namespace sandbox to about page.
>
> This unindents the lines about PID/network namespaces, since those now
> apply to both the setuid or unprivileged namespace sandbox.
>
> BUG=312380
> Committed: https://crrev.com/1ef7ee1ee899087d8632a4f905a3a11697a20b81
> Cr-Commit-Position: refs/heads/master@{#315116}
Review URL: https://codereview.chromium.org/872143006
Cr-Commit-Position: refs/heads/master@{#315541}
4 files changed
