Fix URL override not being used for API calls

The openapi generated `ApiClient`/`Configuration` classes have a way to
to pass scheme, host, and base_path but `Configuration#server_settings`
and `Configuration#server_variables` is used unless server_index is set
to `nil`

app/models/manageiq/providers/cisco_intersight/manager_mixin.rb

@@ -142,17 +142,16 @@ def verify_provider_connection(api_client)
     def raw_connect(url, verify_ssl, key_id, key)
       require "intersight_client"
 
-      uri    = URI.parse(url || "https://intersight.com")
-      scheme = uri.scheme
-      host   = "#{uri.host}:#{uri.port}"
-
       verify_ssl = OpenSSL::SSL::VERIFY_PEER if verify_ssl.nil?
       verify_ssl = verify_ssl == OpenSSL::SSL::VERIFY_PEER
 
       IntersightClient::ApiClient.new(
         IntersightClient::Configuration.new do |config|
-          config.scheme     = scheme
-          config.host       = host
+          if url && url != IntersightClient::Configuration.default.base_url
+            server = url.gsub(/^\w+:\/\//, "")
+            config.server_variables[:server] = server
+          end
+
           config.verify_ssl = verify_ssl
           config.api_key    = key
           config.api_key_id = key_id