fix deviceProfile json bug

[jidalong]

What type of PR is this?
/kind bug

What this PR does / why we need it:
Once a device is created for the edge node, deviceController may create a device configMap for this edge node. Then we can monut this configmap to mapper container。 In my knowledge, the deviceProfile.json file is an example for modbus device configmap, but the in the kubeedge code，the filed of protocol config in configmap is named protocol_config not protocolConfig. And the mapper also use the protocol_config not protocolConfig to prase the dpl json.
Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[kubeedge-bot]

Welcome @jidalong! It looks like this is your first PR to kubeedge/kubeedge 🎉

[fisherxu]

@jidalong Thanks for the fixing! I think we shoud modify all protocol_config to protocolConfig? cc @luogangyi

[luogangyi]

I am sure it is protocolConfig after KubeEdge v1.4
see configmap I get from in running env

{
	"deviceInstances": [{
		"id": "sensor-tag-instance-customized-02",
		"name": "sensor-tag-instance-customized-02",
		"protocol": "modbus-sensor-tag-instance-customized-02",
		"model": "sensor-tag-model",
		"twins": [{
			"propertyName": "temperature-enable",
			"desired": {
				"value": "OFF",
				"metadata": {
					"timestamp": "1550049403598",
					"type": "string"
				}
			},
			"reported": {
				"value": "OFF",
				"metadata": {
					"timestamp": "1550049403598",
					"type": "string"
				}
			}
		}],
		"propertyVisitors": [{
			"name": "temperature",
			"propertyName": "temperature",
			"modelName": "sensor-tag-model",
			"protocol": "modbus",
			"reportCycle": 1000000000,
			"collectCycle": 500000000,
			"customizedValues": {
				"def1": "def1-val",
				"def2": "def2-val",
				"def3": {
					"innerDef1": "idef-val"
				}
			},
			"visitorConfig": {
				"register": "DiscreteInputRegister",
				"offset": 1,
				"limit": 2,
				"scale": 1,
				"isSwap": true,
				"isRegisterSwap": true
			}
		}, {
			"name": "temperature-enable",
			"propertyName": "temperature-enable",
			"modelName": "sensor-tag-model",
			"protocol": "modbus",
			"visitorConfig": {
				"register": "DiscreteInputRegister",
				"offset": 3,
				"limit": 1,
				"scale": 1,
				"isSwap": true,
				"isRegisterSwap": true
			}
		}]
	}],
	"deviceModels": [{
		"name": "sensor-tag-model",
		"properties": [{
			"name": "temperature",
			"dataType": "int",
			"description": "temperature in degree celsius",
			"accessMode": "ReadWrite",
			"defaultValue": 0,
			"maximum": 100,
			"unit": "degree celsius"
		}, {
			"name": "temperature-enable",
			"dataType": "string",
			"description": "enable data collection of temperature sensor",
			"accessMode": "ReadWrite",
			"defaultValue": "OFF"
		}, {
			"name": "pressure",
			"dataType": "int",
			"description": "pressure in degree celsius",
			"accessMode": "ReadWrite",
			"defaultValue": 0,
			"maximum": 100,
			"unit": "Pa"
		}]
	}],
	"protocols": [{
		"name": "modbus-sensor-tag-instance-customized-02",
		"protocol": "modbus",
		"protocolConfig": {
			"slaveID": 1
		},
		"protocolCommonConfig": {
			"com": {
				"serialPort": "1",
				"baudRate": 115200,
				"dataBits": 8,
				"parity": "even",
				"stopBits": 1
			},
			"customizedValues": {
				"pdef1": "pdef1-val",
				"pdef2": "pdef2-val"
			}
		}
	}]
}

[fisherxu]

I am sure it is protocolConfig after KubeEdge v1.4
see configmap I get from in running env

Okey, so please modify all protocol_config to protocolConfig in modbus mapper.

[jidalong]

I am sure it is protocolConfig after KubeEdge v1.4
see configmap I get from in running env

Okey, so please modify all protocol_config to protocolConfig in modbus mapper.
Okey, got it. I will modify all protocol_config to protocolConfig in modbus mapper.

[fisherxu]

/lgtm

[fisherxu]

/approve

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