legion: fixing some uninitialized fields for detach operations
legion: fixing some uninitialized fields for detach operations

StanfordLegion/legion,StanfordLegion/legion,chuckatkins/legion,StanfordLegion/legion,sdalton1/legion,sdalton1/legion,sdalton1/legion,sdalton1/legion,StanfordLegion/legion,chuckatkins/legion,chuckatkins/legion,chuckatkins/legion,sdalton1/legion,StanfordLegion/legion,StanfordLegion/legion,chuckatkins/legion,sdalton1/legion,StanfordLegion/legion,chuckatkins/legion,chuckatkins/legion,StanfordLegion/legion