set: make set_consume() actually free the allocated string if the string already is in the set

(cherry picked from commit 575ccc1b69)

Conflicts:
	src/shared/hashmap.c

src/shared/set.c

@@ -54,7 +54,7 @@ int set_consume(Set *s, void *value) {
         int r;
 
         r = set_put(s, value);
-        if (r < 0)
+        if (r <= 0)
                 free(value);
 
         return r;