malformed transaction posted on peer/transactions makes the server crash

[fix]

Wondering why all servers of testnet recently crashed?

if you post a transaction similar to this (no recipientId)

{
  amount: 100000000,
  asset: {},
  fee: 10000000,
  id: "8233217121578014269",
  senderPublicKey: "5f7400e4c1ac021617fbc93bb9a51661855ce29d591896821252300ff1e437f3",
  signSignature: "8923786b20813bb9ac69e6c18a124918631dc3ea299d68428a8268000c979cebb2efc4441a7efa6713d09454b32d86292a6a7b22c49310bb64a674cc9b636008",
  signature: "0a42096400682a0389e5d61dcefa470be857dfdc38b44d0987b66658dbc596a39aaeea712896cbd78aca707ce9ad5fdff01576e0b466302711ff50b8dfc06001",
  timestamp: 30139064,
  type: 0
}

Boom!

details on the server log:

fatal Domain master { 
  message: 'Cannot read property 'toLowerCase' of undefined',
  stack: 'TypeError: Cannot read property 'toLowerCase' of undefined
             at l.verify (/home/liskdelegate/lisk-0.1.1-Linux-x86_64/app.js:10:19543)
             at l.verify (/home/liskdelegate/lisk-0.1.1-Linux-x86_64/app.js:13:646)
             at /home/liskdelegate/lisk-0.1.1-Linux-x86_64/app.js:11:1208
             at EventEmitter.<anonymous> (/home/liskdelegate/lisk-0.1.1-Linux-x86_64/app.js:12:29429)
             at Socket.<anonymous> (/home/liskdelegate/lisk-0.1.1-Linux-x86_64/node_modules/dblite/build/dblite.node.js:379:22)
             at Socket.emit (events.js:107:17)
             at readableAddChunk (_stream_readable.js:163:16)
             at Socket.Readable.push (_stream_readable.js:126:10)
             at Pipe.onread (net.js:540:20)'
 }