Sometimes Can not search only with `:u' option or `:?url' keyword.

SBCL:

```lisp
(qs:? "quicksearch" :u)
```

or

```lisp
(qs:quicksearch "quicksearch" :?url t)
```

SLDB:

```
The value
  NIL
is not of type
  HASH-TABLE
   [Condition of type TYPE-ERROR]
```

REPL:

```
; Evaluation aborted on #<TYPE-ERROR expected-type: "HASH-TABLE"datum: NIL>.
```