Request "sides-supported" and "sides-default" attributes through
IPP if there is no PPD for selected printer.
Pass "sides" option with other options in printer_get_options().
Add function setup_ipp_option() for creating of IPP option
of given name with passed choices and default value.
Mark such an option as "is-ipp-option" so we can distinguish it
later.
https://bugzilla.gnome.org/show_bug.cgi?id=725441
493aa4e9b3