Allow to add datawarehouse provider with a port other than 80

When adding a datawarehouse provider, port 80 is being used for
the "default" role endpoint, even if a different port was specified.

app/models/manageiq/providers/hawkular/datawarehouse_manager.rb

@@ -9,7 +9,9 @@ class Hawkular::DatawarehouseManager < ManageIQ::Providers::DatawarehouseManager
     include AuthenticationMixin
 
     DEFAULT_PORT = 80
-    default_value_for :port, DEFAULT_PORT
+    default_value_for :port do |provider|
+      provider.port || DEFAULT_PORT
+    end
 
     def verify_credentials(_auth_type = nil, options = {})
       connect(options).fetch_version_and_status