Fixed issue with the flush interval.
Fixed issue with the flush interval.

The flush interval should be specified in milliseconds.  The
flush interval calculation was using the check frequency which
is in seconds.  The result needed to be converted to milliseconds.

Change-Id: Ib25bd9d1c1a5bda50fa87beb39605c2dc7c9d34d

sapcc/monasca-agent,sapcc/monasca-agent,sapcc/monasca-agent