e_comp_object: set 'showing' flag early
e_comp_object: set 'showing' flag early

It was possible to emit show animation multiple times, if 'showing' flag
is set after animation began. So let it set before doing animation.

Change-Id: Idb844511799f7cfb26f4f5017ffa517b32c462ce
Signed-off-by: MinJeong Kim <24556705797ea9c691c6aa52e5846988e670d796@samsung.com>

tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment,tizenorg/platform.upstream.enlightenment