legion_prof_rs: Fix a bug in definition of Proc::is_empty().
legion_prof_rs: Fix a bug in definition of Proc::is_empty().

StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion,StanfordLegion/legion