VOL-1497 : Add more control to kv/memory access

- Added kv locking mechanism (etcd only)
- (watch) control path access whenever possible
- (watch) use a transaction for updates and merge with memory
- cleaned up vendoring
- misc changes to fix exceptions found along the way

Amendments:

- Copyright header got removed in auto-generated file
- Changed default locking to false for KV list operation
- Updated backend api to allow the passing of locking parameter

Change-Id: Ie1a55d3ca8b9d92ae71a85ce42bb22fcf1419e2c
diff --git a/rw_core/core/device_agent.go b/rw_core/core/device_agent.go
index af717ef..b321f22 100644
--- a/rw_core/core/device_agent.go
+++ b/rw_core/core/device_agent.go
@@ -140,7 +140,7 @@
 // getDeviceWithoutLock is a helper function to be used ONLY by any device agent function AFTER it has acquired the device lock.
 // This function is meant so that we do not have duplicate code all over the device agent functions
 func (agent *DeviceAgent) getDeviceWithoutLock() (*voltha.Device, error) {
-	if device := agent.clusterDataProxy.Get("/devices/"+agent.deviceId, 0, false, ""); device != nil {
+	if device := agent.clusterDataProxy.Get("/devices/"+agent.deviceId, 0, true, ""); device != nil {
 		if d, ok := device.(*voltha.Device); ok {
 			cloned := proto.Clone(d).(*voltha.Device)
 			return cloned, nil