input-panel: Fix show_input_panel_surface crash when no surface has focus
input-panel: Fix show_input_panel_surface crash when no surface has focus

Signed-off-by: Nicolas Guyomard <eceee2e3706eeda91c45eedcd8b5f6e883f209f8@open.eurogiciel.org>
Signed-off-by: Derek Foreman <2f97e0f0bc172406aab8ccd42dab54c95bab8759@osg.samsung.com>
Reviewed-by: Bryce Harrington <bdb14cfc1ab8d24e13de84adc40b41ae60c13bd1@osg.samsung.com>

Gnurou/weston,krezovic/weston,kwm81/weston,sir-murray/weston,giucam/weston,kwm81/weston,Fantu/compositor-spice,Gnurou/weston,sir-murray/weston,giucam/weston,krezovic/weston,Fantu/compositor-spice,Fantu/compositor-spice