Fixed the script saving issue in CustomizationTemplate in PXE Controller

Added missing :serialize key to the :locals hash

https://bugzilla.redhat.com/show_bug.cgi?id=1114756
Merge pull request #174 from AparnaKarve/bz1114756_save_script_issue_in_customization_templ

Fixed the script saving issue in CustomizationTemplate in PXE Controller