Please describe the problem:
Print dialogs created by gtk_print_operation_new() set the wrong options on cups printers that have "instances" defined in /etc/cups/lpoptions or ~/.{,cups/}lpoptions

Instances are defined for example like this (in the mentioned files):

---snip---------------------------------------------------
Default CMP600 CNDensity=-10 CNGamma=1.4 ...
Dest CMP600/Draft CNDensity=-10 CNGamma=1.8 ...
---snap---------------------------------------------------

this snippet defines:
- on the first line: the options for a "Default" (could also be "Dest") printer "CMP600"
- on the second line: another "instance" of that printer called "Draft", with different options

The code in gtk silently ignores the fact that the second line defines "instance" options and sets the options for the default instance of the printer, which is the only instance showing up in the print dialog as the gtk_print_operation_new dialog doesn't handle instances at all (yet).

The relevant code is in
file /modules/printbackends/cups/gtkprintbackendcups.c
function cups_parse_user_options():

---snip---------------------------------------------------
      /* NUL-terminate the name, stripping the instance name */
      name = lineptr;
      while (!isspace (*lineptr) && *lineptr)
        {
          if (*lineptr == '/')
            *lineptr = '\0';
          lineptr++;
        }
---snap----------------------------------------------------

I would suggest to remove that statement
>            *lineptr = '\0';
and put
>            break;
instead.

I am just going to check if that would work now...


Steps to reproduce:
1. declare some instances (with kde printers control for example: "$ kcmkcmshell printers")
2. cat the relevant files "cat /etc/cups/lpoptions ~/.{,cups/}lpoptions" to make sure they show up there. the bug probably only occures if the instances are declared _after_ the default printer options as the code then overwrites the default options


Actual results:
3. hit control-p to print from gedit / firefox / evoultion / ... and notice that the options for your printer are those declared in the instance declared _last_ in the lpoptions config files


Expected results:
the default options should show up instead of the instance options

Does this happen every time?
yes

Other information:
it should be mentioned that gnome-cups-manager sems to handle this correctly already and much of the code is anyway duplicated there. but gnome-cups-manager seems not to be used that much