use scoped_r/wlock instead of scoped_lock for rw_mutex fix #769
use scoped_r/wlock instead of scoped_lock for rw_mutex fix #769

jubatus/jubatus,gintenlabo/jubatus,mathn/jubatus,mathn/jubatus,rimms/jubatus,elkingtonmcb/jubatus,roselleebarle04/jubatus,kmaehashi/jubatus,elkingtonmcb/jubatus,Asuka52/jubatus,jubatus/jubatus,roselleebarle04/jubatus,jubatus/jubatus,rimms/jubatus,gintenlabo/jubatus,Asuka52/jubatus,kmaehashi/jubatus