Fix authentication of metrics credentials in RHV

When the database name was not the default one the RHV metrics credentials
would not use the right database name during authentication and fail.

app/models/manageiq/providers/redhat/infra_manager/api_integration.rb

@@ -134,7 +134,7 @@ def rhevm_metrics_connect_options(options = {})
     server   = options[:hostname] || metrics_hostname || hostname
     username = options[:user] || authentication_userid(:metrics)
     password = options[:pass] || authentication_password(:metrics)
-    database = options[:database]
+    database = options[:database] || history_database_name
 
     {
       :host     => server,