The changeOpen status is cached in the PatchSetApprovals
table for performance reasons, so the approvals must
be updated whenever the change status changes. This
update is done in a few places and is likely not
ever obvious why the update is being done. Make
a function to do the update which makes the code
self documenting all while sharing the
implementation. Create an new ApprovalsUtil class
for this function which can be a good place for
more approval manipulating functions in the future.
Change-Id: If92f3757963048a141003304f2c96036c915ab89
052918a23a