util/logger: fix grpc log redirection (#4050)
util/logger: fix grpc log redirection (#4050)

Signed-off-by: Neil Shen <cce998fdf3749d1bb26a297634a107d1dc0875fa@gmail.com>
BusyJay/tikv,c4pt0r/tikv,BusyJay/tikv,BusyJay/tikv,BusyJay/tikv,pingcap/tikv,pingcap/tikv