Fix #3982 - Get rid of URI in hp_sys_mgmt_login because it's not used at all

The hp_sys_mgmt_login module will pass datastore['URI'] to Metasploit::Framework::LoginScanner::Smh, but Metasploit::Framework::LoginScanner::Smh does not care because this is what it does:

```ruby
          req_opts = {
            'method' => 'POST',
            'uri'    => '/proxy/ssllogin',
            'vars_post' => {
              'redirecturl'         => '',
              'redirectquerystring' => '',
              'user'                => credential.public,
              'password'            => credential.private
            }
          }
```

See: https://github.com/rapid7/metasploit-framework/blob/master/lib/metasploit/framework/login_scanner/smh.rb

I don't think it's necessary to provide verification steps at all, because this is really easy.