Remove log message about unused definition on startup

[Tschakki]

Expected behavior

When starting the node from Source, no logs should be visible in the console, if everything is running correctly.

Actual behavior

The following log is thrown on startup:

node app.js --network testnet
[{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/CommonBlock","path":["definitions","CommonBlock"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: #/definitions/PeersList","path":
["definitions","PeersList"]},{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSPeerHeaders","path":["definitions","WSPeerHeaders"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSPeerUpdateRequest","path":["definitions","WSPeerUpdateRequest"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSSignaturesList","path":["definitions","WSSignaturesList"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: #/definitions/WSBlocksList","path":
["definitions","WSBlocksList"]},{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSBlocksCommonRequest","path":["definitions","WSBlocksCommonRequest"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSTransactionsRequest","path":["definitions","WSTransactionsRequest"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSAccessObject","path":["definitions","WSAccessObject"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSTransactionsResponse","path":["definitions","WSTransactionsResponse"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSSignaturesResponse","path":["definitions","WSSignaturesResponse"]},
{"code":"UNUSED_DEFINITION","message":"Definition is not used: 
#/definitions/WSBlocksBroadcast","path":["definitions","WSBlocksBroadcast"]}] 2

Steps to reproduce

Set up Lisk Core from Source

Which version(s) does this affect? (Environment, OS, etc...)

Lisk Core v1.3.1, Ubuntu 16.04

[MaciejBaj]

Hey @Tschakki we have the issue opened for that already - #1805.