Upgrade enunciate version to 1.28
  -Convert XmlElementRef to XmlElement to allow doc generation to work properly
  -Add swagger module dependency to enunciate

Change-Id: Ia41e7733bd44965951ca83aaa7738e2df74151da
Signed-off-by: mrajvaid <mrajvaid@cisco.com>
Merge "Upgrade enunciate version to 1.28   -Convert XmlElementRef to XmlElement to allow doc generation to work properly   -Add swagger module dependency to enunciate"