rest: do not retrieve the metric twice in get_all()
rest: do not retrieve the metric twice in get_all()

We used to retrieve it once for enforce() and then one for returning. Do
that once and for all!

Change-Id: I5d81fcda95a266af02ca5123e409045eaa771f45

gnocchixyz/gnocchi,sileht/gnocchi,idegtiarov/gnocchi-rep,leandroreox/gnocchi,gnocchixyz/gnocchi,idegtiarov/gnocchi-rep,leandroreox/gnocchi,idegtiarov/gnocchi-rep,sileht/gnocchi