Fix for do_request and extra parameters containing path params and query string params

[denyago]

When dealing with path like /items_a/:items_a_id/items_b/:id and using do_request with :items_a_id, :id and :an_extra_param, do_request calls path 2 times:

• first to set path_or_query,
• second to set path in case of :get method.

But call to path, deletes :items_a_id and :id from extra_params hash. So at the end, path is equal to /items_a/:items_a_id/items_b/:id?an_extra_param=

[samwgoldman]

Looks good to me. @oestrich?

[samwgoldman]

Thanks @denyago!