Use the ppd groups "name" instead of "text" (bug #687065)

This commit fixes a regression caused by a patch to remove Cups 1.2
ifdefs. This resulted in the "installable options" to appear in the
print dialog.

modules/printbackends/cups/gtkprintbackendcups.c

@@ -3169,7 +3169,7 @@ value_is_off (const char *value)
 static char *
 ppd_group_name (ppd_group_t *group)
 {
-  return group->text;
+  return group->name;
 }
 
 static int