fw: NccStrategy remembers only best face

refs #1961

Strategy::beforeSatisfyPendingInterest is renamed to
Strategy::beforeSatisfyInterest, so as to match the semantics of this trigger.
This is a backwards-incompatible change that requires function renaming in
all subclasses of Strategy class.

LimitedIo::afterOp gets a bugfix that allows it to be invoked out of
LimitedIo::run without leaving io_service unusable.

Change-Id: Ia4c632beb62c554724b83846a3d6358ae08779ad