Fix issue in class_dataDomain.rb to return early when domain is empty

Author: jwaspin

lib/adiwg/mdtranslator/writers/fgdc/classes/class_dataDomain.rb

@@ -33,6 +33,7 @@ def writeXML(domainId, inContext = nil)
                   end
                   if hDomain.empty?
                      @NameSpace.issueError(70, domainId)
+                     return
                   end
 
                   outContext = domainId