ZED: Fix uninitialized value reads

Coverity complained about a couple of uninitialized value reads in ZED.

 * zfs_deliver_dle() can pass an uninitialized string to zed_log_msg()
 * An uninitialized sev.sigev_signo is passed to timer_create()

The former would log garbage while the latter is not a real issue, but
we might as well suppress it by initializing the field to 0 for
consistency's sake.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #14047

cmd/zed/agents/fmd_api.c

@@ -616,6 +616,7 @@ fmd_timer_install(fmd_hdl_t *hdl, void *arg, fmd_event_t *ep, hrtime_t delta)
 	sev.sigev_notify_function = _timer_notify;
 	sev.sigev_notify_attributes = NULL;
 	sev.sigev_value.sival_ptr = ftp;
+	sev.sigev_signo = 0;
 
 	timer_create(CLOCK_REALTIME, &sev, &ftp->ft_tid);
 	timer_settime(ftp->ft_tid, 0, &its, NULL);

cmd/zed/agents/zfs_mod.c

@@ -1135,6 +1135,7 @@ zfs_deliver_dle(nvlist_t *nvl)
 		strlcpy(name, devname, MAXPATHLEN);
 		zfs_append_partition(name, MAXPATHLEN);
 	} else {
+		sprintf(name, "unknown");
 		zed_log_msg(LOG_INFO, "zfs_deliver_dle: no guid or physpath");
 	}