fix segmentation fault in chat.qml
fix segmentation fault in chat.qml

Change-Id: I14201cd2a8649bc816f0f505c2917eed0184d853
Reviewed-on: http://cr.qtquick.me/448
Tested-by: http://ci.qtquick.me/
Reviewed-by: Tasuku Suzuki <42980d970444f9101663582e70cd53623b3238b4@gmail.com>
Tested-by: Tasuku Suzuki <42980d970444f9101663582e70cd53623b3238b4@gmail.com>

yatsek/silk,qt-users-jp/silk,qt-users-jp/silk,yatsek/silk,yatsek/silk,qt-users-jp/silk,qt-users-jp/silk,yatsek/silk