aplaymidi: Set event completely for tempo event

aplaymidi: Set event completely for tempo event

After UMP support was added in b399fb8 ev.type setting was inadvertently
dropped in the code path handling tempo meta event.
This is causing tempo meta events to not be handled at all.
Moreover, snd_seq_ev_set_fixed is also missing so MIDI files with
variable events such as SYSEX before the tempo meta event usually are
causing a segfault.

Fixes: b399fb85a919 ("aplaymidi: Add UMP support")
Closes: https://github.com/alsa-project/alsa-utils/issues/241
Signed-off-by: Takashi Iwai <tiwai@suse.de>