Register container grace timers on warden restart

Signed-off-by: Maria Shaldibina <mariash@pivotallabs.com>
Register the client with all containers on reconnect

[#62709652]

Signed-off-by: Alex Choi, achoi <a.achoi@pivotallabs.com>
Move the checks for number of connections into setup_grace_timer

The public setup_grace_timer should take care of checks before firing
timer.

Signed-off-by: Maria Shaldibina <mariash@pivotallabs.com>