Allow discovery to be turned off in fabric-network

The Gateway API enables discovery by default (hard coded).
The Client API disables discovery by default but allows it
to be turned on using the mechanism in Config.js
This patch changes the gateway API to default discovery to
‘true’ but allow it to be overridden by the above mechanism.
By removing the setting from default.json, it will pick up the
default value from the code (false in channel.js, true in gateway.js)

Change-Id: I068e302cae888e414371766dfee049fabb59b8ff
Signed-off-by: andrew-coleman <andrew_coleman@uk.ibm.com>

fabric-client/config/default.json

@@ -23,7 +23,6 @@
 		"1.0": "./impl/NetworkConfig_1_0.js"
 	},
 	"grpc-wait-for-ready-timeout": 3000,
-	"initialize-with-discovery": false,
 	"discovery-as-localhost": true,
 	"discovery-cache-life": 300000,
 	"discovery-protocol": "grpcs",

fabric-network/lib/gateway.js

@@ -104,7 +104,7 @@ class Gateway {
 				strategy: EventStrategies.MSPID_SCOPE_ALLFORTX
 			},
 			discovery: {
-				enabled: true
+				enabled: Client.getConfigSetting('initialize-with-discovery', true)
 			}
 		};
 	}