InvalidChangeOperationExceptions are only thrown when we pass a null
change to this method. It is better that we just don't pass the change
and add a more useful error to the ReviewResult.
We no longer perform a check to see if the patchset we have is the most
current one. restore/abandon happens at the change level and the
patchset is just fetched to append a message to the change.
Change-Id: I3b3af1e3982fcd9111214a7c66a28476189c923b
8f258d9972