[devtools jail] fix NULL pointer dereference
[devtools jail] fix NULL pointer dereference

Fix rogerwang/node-webkit#793

ondra-novak/blink,ondra-novak/blink,ondra-novak/blink,ondra-novak/blink,ondra-novak/blink,ondra-novak/blink,ondra-novak/blink,ondra-novak/blink,ondra-novak/blink