Revert "tree-wide: use CONF_FILES_CHASE_BASENAME where root directory is specified"

This reverts commit 6b606f3586.

The commit was mistakenly merged without review, and has several issues.
Let's revert at least now.

src/shared/install.c

@@ -3298,9 +3298,7 @@ static int presets_find_config(RuntimeScope scope, const char *root_dir, char **
         else
                 assert_not_reached();
 
-        return conf_files_list_strv(files, ".preset", root_dir,
-                                    CONF_FILES_REGULAR | CONF_FILES_CHASE_BASENAME | CONF_FILES_FILTER_MASKED,
-                                    dirs);
+        return conf_files_list_strv(files, ".preset", root_dir, 0, dirs);
 }
 
 static int read_presets(RuntimeScope scope, const char *root_dir, UnitFilePresets *presets) {