eventdemo: use zalloc
eventdemo: use zalloc

Zero-initialize the struct, just in case.

Signed-off-by: Pekka Paalanen <0f6ae7001e34c37b02fb2c1c2573ddf8f442136a@collabora.co.uk>
Reviewed-by: Yong Bakos <d0d6c2a9047d8c98cd8ce1e9b46eb851dcd10a82@humanoriented.com>
Tested-by: Yong Bakos <d0d6c2a9047d8c98cd8ce1e9b46eb851dcd10a82@humanoriented.com>
Reviewed-by: Benoit Gschwind <6d0fcc95e39ab8ccb88bafebb2075e9d5c92b713@gnu-log.net>
Tested-by: Benoit Gschwind <6d0fcc95e39ab8ccb88bafebb2075e9d5c92b713@gnu-log.net>

giucam/weston,giucam/weston,krezovic/weston,krezovic/weston,Gnurou/weston,sir-murray/weston,sir-murray/weston,Gnurou/weston