hook: spiceoptions: To provide spice option attributes to vm

This hook goes through VM definitions xml file and manipulate its
graphics device if the protocol type is spice. This can be used to
configure spice options. This hook script will be really useful to
configure some of the spice optimization attributes and values
like image, streaming, clipboard..etc

For ex:

  <graphics type='spice' port='-1' tlsPort='-1' autoport='yes'>
     ******
    <image compression='auto_glz'/>
    <streaming mode='filter'/>
    <mouse mode='client'/>
  </graphics>

Change-Id: I7761aab98cdc3a0d37bed7984ae540278e6bbf70
Signed-off-by: Humble Chirammal <hchiramm@redhat.com>
Signed-off-by: Amador Pahim <apahim@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/22178
Reviewed-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-by: Michal Skrivanek <michal.skrivanek@redhat.com>
Reviewed-by: Francesco Romani <fromani@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>