Recycle control connection every cbclient.recycleBucketMonitorAfter

Default value for cbclient.recycleBucketMonitorAfter is 60 seconds

A long polling control connection on BucketMonitor can become stale.
Upstream can crash and even with tcp keepalive enabled (see fix1 rev
bff8edd), tcp keep alive settings on a particular environment can be
such, the stale state won't be defected soon enough.

Solution 2 is to recycle the connection periodically: A timer is
set to recycle the connection every cbclient.recycleBucketMonitorAfter
millis.