There was a bug in HA subnet router handover where we used stale node data
from the longpoll session that we handed to Connect. This meant that we got
some odd behaviour where routes would not be deactivated correctly.
This commit changes to the nodeview is used through out, and we load the
current node to be updated in the write path and then handle it all there
to be consistent.
Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
b904276f2b