I missed connecting some controlknobs.Knobs pieces in 4e91cf20a8
resulting in that breaking control knobs entirely.
Whoops.
The fix in ipn/ipnlocal (where it makes a new controlclient) but to
atone, I also added integration tests. Those integration tests use
a new "tailscale debug control-knobs" which by itself might be useful
for future debugging.
Updates #9351
Change-Id: Id9c89c8637746d879d5da67b9ac4e0d2367a3f0d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
7c1ed38ab3