update changelog-3.4 to protection for rangePermCache with a RW lock
update changelog-3.4 to protection for rangePermCache with a RW lock

Signed-off-by: Hitoshi Mitake <f5d714bdcbd540cbcf6bb2062e1b0243e2f5e923@gmail.com>

mqliang/etcd,ajityagaty/etcd,mqliang/etcd,etcd-io/etcd,mqliang/etcd,etcd-io/etcd,etcd-io/etcd,ajityagaty/etcd,ajityagaty/etcd