Duplicate logs when Error or Warning

[Andrea-Campanella]

Describe the bug
Logging is duplicated when is Error or Warning

To Reproduce
Steps to reproduce the behavior:

1. Run make run-docker
2. docker logs <container_id>
3. check any error or warning log.

Expected behavior
The log should be issued just once.

Screenshots
W0624 12:43:20.940243 1 synchronizer.go:60] could not create a gNMI client: Dialer(localhost:50001, 5s): context deadline exceeded
W0624 12:43:20.940243 1 synchronizer.go:60] could not create a gNMI client: Dialer(localhost:50001, 5s): context deadline exceeded
W0624 12:43:20.940358 1 factory.go:43] Error in connecting to client: could not create a gNMI client: Dialer(localhost:50001, 5s): context deadline exceeded
W0624 12:43:20.940358 1 factory.go:43] Error in connecting to client: could not create a gNMI client: Dialer(localhost:50001, 5s)

[Andrea-Campanella]

log.SetOutput(os.Stdout) line 93 of onos-config

[Andrea-Campanella]

this could be easily fixed by doing

log.InitFlags(nil) for klog
but if other projects in the dependency set import glog the two are not compatibile and an error is thrown at runtime

/var/folders/4q/4x8mxbcd6hxbg79vtn04jjsr0000gn/T/go-build901010861/b001/exe/onos-config flag redefined: log_dir
panic: /var/folders/4q/4x8mxbcd6hxbg79vtn04jjsr0000gn/T/go-build901010861/b001/exe/onos-config flag redefined: log_dir

goroutine 1 [running]:
flag.(*FlagSet).Var(0xc000092120, 0x46cd6c0, 0x4acfa90, 0x460dd8c, 0x7, 0x4625087, 0x2f)
	/usr/local/go/src/flag/flag.go:850 +0x4af
flag.(*FlagSet).StringVar(...)
	/usr/local/go/src/flag/flag.go:753
k8s.io/klog.InitFlags(0x0)
	/Users/andrea/go/pkg/mod/k8s.io/klog@v0.3.3/klog.go:427 +0x9d
main.main()
	/Users/andrea/go/src/github.com/onosproject/onos-config/cmd/onos-config/onos-config.go:76 +0x3f

This is a know problem see:
kubernetes/client-go#83
kubernetes/client-go#19
The solution proposed in #398 was found here
https://github.com/kubernetes/klog/blob/master/README.md
https://github.com/kubernetes/klog/blob/master/examples/coexist_glog/coexist_glog.go