Sync allocation state before waiting for a destroy
Sync allocation state before waiting for a destroy

This change ensures that the client syncs allocation state with the
servers before entering its wait loop for the allocation to be
destroyed.

Fixes https://github.com/hashicorp/nomad/issues/2563

burdandrei/nomad,kmalec/nomad,hashicorp/nomad,Ashald/nomad,frundh/nomad,kmalec/nomad,burdandrei/nomad,nak3/nomad,dvusboy/nomad,dvusboy/nomad,novilabs/nomad,frundh/nomad,diptanu/nomad,Ashald/nomad,frundh/nomad,diptanu/nomad,diptanu/nomad,novilabs/nomad,diptanu/nomad,dvusboy/nomad,nak3/nomad,burdandrei/nomad,diptanu/nomad,frundh/nomad,diptanu/nomad,hashicorp/nomad,nak3/nomad,dvusboy/nomad,dvusboy/nomad,Ashald/nomad,novilabs/nomad,Ashald/nomad,nak3/nomad,burdandrei/nomad,frundh/nomad,hashicorp/nomad,frundh/nomad,kmalec/nomad,Ashald/nomad,hashicorp/nomad,kmalec/nomad,kmalec/nomad,burdandrei/nomad,Ashald/nomad,hashicorp/nomad,diptanu/nomad,novilabs/nomad,frundh/nomad,kmalec/nomad,nak3/nomad,novilabs/nomad,novilabs/nomad,hashicorp/nomad,nak3/nomad,burdandrei/nomad,nak3/nomad,burdandrei/nomad,dvusboy/nomad,kmalec/nomad,Ashald/nomad,novilabs/nomad,dvusboy/nomad