control: Make decrease interval optional

The `decrease_interval` configuration attribute should be optional where
it defaults to 0 when not given. A decrease interval of 0 disables the
decrease timer.

Change-Id: Ie88d94edb286870c7b8965a4ee778c89c08cc00e
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
2 files changed