fix eval_pattern

@@ -28,7 +28,8 @@ class DsAdmin::Storage::Config
     result = String.new
     pattern.scan(scan_exp) do |m|
       key = m[2][1..m[2].length].to_sym if m[2]
-      val = eval('"' + data[key] + '".send ' + m[4]) if data[key] && m[4]
+      val = data[key] if data[key]
+      val = eval('"' + val + '".send ' + m[4]) if val && m[4]
 
       result += m[0] + (val || "")
     end