Crash if there is BLE device with no name set nearby

[StevenRudenko]

Put a BLE device without name set near drone and try to connect within: node examples/keyboard/drone.js

ER: Seach finds drone and connects to it AR: Crash ->

info: Searching for drones...
/Users/stepan/dev/other/npm-parrot-minidrone/lib/MiniDroneBtAdapter.js:406
        const localNameMatch = matchesFilter || DRONE_PREFIXES.some((prefix) => localName.indexOf(prefix) >= 0);
                                                                                          ^

TypeError: Cannot read property 'indexOf' of undefined
    at DRONE_PREFIXES.some (/Users/stepan/dev/other/npm-parrot-minidrone/lib/MiniDroneBtAdapter.js:406:91)
    at Array.some (<anonymous>)
    at MiniDroneBtAdapter.validatePeripheral (/Users/stepan/dev/other/npm-parrot-minidrone/lib/MiniDroneBtAdapter.js:406:64)
    at MiniDroneBtAdapter.onPeripheralDiscovery (/Users/stepan/dev/other/npm-parrot-minidrone/lib/MiniDroneBtAdapter.js:315:19)
    at Noble.MiniDroneBtAdapter.noble.on (/Users/stepan/dev/other/npm-parrot-minidrone/lib/MiniDroneBtAdapter.js:98:56)
    at Noble.emit (events.js:160:13)
    at Noble.onDiscover (/Users/stepan/dev/other/npm-parrot-minidrone/node_modules/noble/lib/noble.js:174:10)
    at NobleBindings.emit (events.js:160:13)
    at NobleBindings.<anonymous> (/Users/stepan/dev/other/npm-parrot-minidrone/node_modules/noble/lib/mac/highsierra.js:188:12)
    at /Users/stepan/dev/other/npm-parrot-minidrone/node_modules/noble/lib/mac/uuid-to-address.js:22:5