udev: save stats of all udev rules file

The mtime of directory is not updated when an existing rule file is
changed. Hence, paths_check_timestamp() is not reliable.

src/shared/conf-parser.c

@@ -445,7 +445,7 @@ int config_parse(
         return 1;
 }
 
-static int hashmap_put_stats_by_path(Hashmap **stats_by_path, const char *path, const struct stat *st) {
+int hashmap_put_stats_by_path(Hashmap **stats_by_path, const char *path, const struct stat *st) {
         _cleanup_free_ struct stat *st_copy = NULL;
         _cleanup_free_ char *path_copy = NULL;
         int r;

src/shared/conf-parser.h

@@ -122,6 +122,7 @@ int config_get_stats_by_path(
                 bool check_dropins,
                 Hashmap **ret);
 
+int hashmap_put_stats_by_path(Hashmap **stats_by_path, const char *path, const struct stat *st);
 bool stats_by_path_equal(Hashmap *a, Hashmap *b);
 
 typedef struct ConfigSection {