weston-terminal: Fix crash on first keystroke

Since 894b3rcc634 weston-terminal will crash on first keystroke if you
fail to create an xkb compose state.  This can happen if you don't have
a Compose file.

Instead, now we just return uncomposed symbols.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
1 file changed