ResourceManager.search doesn't take the endpoint path into account

In here:
https://github.com/gnocchixyz/python-gnocchiclient/blob/master/gnocchiclient/v1/resource.py#L174

gnocchiclient does:
url = "v1/search/resource/%s?%%s" % resource_type

Unfortunately, when the endpoint is set to something like this:
http://api.example.com/metric

gnocchiclient then fails to add /metric to the above url = variable, and therefore fails.

The solution would be to check the endpoint, and find the path, to add it before the content of url=