[gegl] gegl: one more s/_context_get_source/_context_dup_object/

[Øyvind Kolås <ok src gnome org>]

commit d9248d1d7fafeb880c4fb08f4a6ba94fad458041
Author: Øyvind Kolås <pippin gimp org>
Date:   Sun Nov 26 12:42:53 2017 +0100

    gegl: one more s/_context_get_source/_context_dup_object/

 gegl/operation/gegl-operation-point-filter.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gegl/operation/gegl-operation-point-filter.c b/gegl/operation/gegl-operation-point-filter.c
index 8137d4e..23ff686 100644
--- a/gegl/operation/gegl-operation-point-filter.c
+++ b/gegl/operation/gegl-operation-point-filter.c
@@ -121,7 +121,7 @@ gegl_operation_filter_process (GeglOperation        *operation,
     return TRUE;
   }
 
-  input  = gegl_operation_context_get_source (context, "input");
+  input  = (GeglBuffer*)gegl_operation_context_dup_object (context, "input");
   output = gegl_operation_context_get_output_maybe_in_place (operation,
                                                              context,
                                                              input,