sanitize k8s namepsaces (#859)

Author: johrstrom

lib/ood_core/job/adapters/kubernetes/batch.rb

@@ -271,7 +271,7 @@ def configmap_name(id)
   end
 
   def namespace
-    "#{namespace_prefix}#{username}"
+    "#{namespace_prefix}#{username.gsub(/[.@]/, '-')}"
   end
 
   def formatted_ns_cmd