Initialize helper structure to 0s

We check the pointers that are part of this structure for NULL before
accessing them - but that means we need to zero out the structure for this
to work.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

uemis.c

@@ -129,7 +129,7 @@ static struct uemis_helper *uemis_get_helper(int diveid)
 		php = &hp->next;
 		break;
 	}
-	hp = *php = malloc(sizeof(struct uemis_helper));
+	hp = *php = calloc(1, sizeof(struct uemis_helper));
 	hp->diveid = diveid;
 	hp->next = NULL;
 	return hp;