b90c340 (feat(transport): Allow custom IO and UDS example (#184),
2019-12-13) changed the Connector type to be more generic instead of
only allowing the HttpConnector type, during this change the
`Service::poll_ready` impl was changed from calling
`MakeConnection::poll_ready` on `self.http` to `self` resulting in
infinite recursion due to the blanket imple of
`MakeConnection::poll_ready` calling `Service::poll_ready`.
This fixes the bug by calling `MakeConnection::poll_ready` on
`self.inner` instead of `self`.
Fixes#191
