[gtk/matthiasc/for-master] Revert "Fix the build with cups < 2.3"

[Matthias Clasen <matthiasc src gnome org>]

commit 028cd1e23aeca91c34c63bebf935778fc452ac4b
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Oct 1 07:59:30 2020 -0400

    Revert "Fix the build with cups < 2.3"
    
    This reverts commit d761e3cf2c31b91269a3dbfd64a553decdeec51c.
    
    I am seeing PPD_CUSTOM_UNKNOWN in the cups headers in our
    ci images, and that is cups 2.2.12. So this commit was
    mistaken.

 modules/printbackends/gtkprintbackendcups.c | 2 --
 1 file changed, 2 deletions(-)
---
diff --git a/modules/printbackends/gtkprintbackendcups.c b/modules/printbackends/gtkprintbackendcups.c
index 982f1c0a6c..b88d76011c 100644
--- a/modules/printbackends/gtkprintbackendcups.c
+++ b/modules/printbackends/gtkprintbackendcups.c
@@ -647,9 +647,7 @@ add_cups_options (const char *key,
                           custom_value = TRUE;
                           break;
 
-#if CUPS_VERSION_MAJOR == 2 && CUPS_VERSION_MINOR >= 3
                         case PPD_CUSTOM_UNKNOWN:
-#endif
                         default :
                           custom_value = FALSE;
                         }