map: remove unused function

map.c

@@ -301,19 +301,6 @@ const Map *map_prefix(const Map *map, const char *prefix)
 	return top;
 }
 
-bool map_prefix_delete(Map *map, const char *prefix)
-{
-	bool ret = false;
-	do {
-		const char *conflict = NULL;
-		const Map *conflicts = map_prefix(map, prefix);
-		if (!map_first(conflicts, &conflict))
-			break;
-		ret = map_delete(map, conflict);
-	} while (ret);
-	return ret;
-}
-
 static void clear(Map n)
 {
 	if (!n.v) {

map.h

@@ -34,8 +34,6 @@ void map_iterate(const Map*, bool (*handle)(const char *key, void *value, void *
 /* Return a submap matching a prefix. This returns a pointer into the
  * original map, so don't alter the map while using the return value. */
 const Map *map_prefix(const Map*, const char *prefix);
-/* Delete all entries of the prefix map */
-bool map_prefix_delete(Map*, const char *prefix);
 /* Test whether the map is empty i.e. contains no elements */
 bool map_empty(const Map*);
 /* Remove every member from the map. The map will be empty after this. */