[niepce] Remove an unused header

[Hubert Figuière <hub src gnome org>]

commit ef7fc6ae4b0a1bd8532532a835aacf48a00249cb
Author: Hubert Figuière <hub figuiere net>
Date:   Tue Sep 27 23:03:26 2022 -0400

    Remove an unused header

 src/fwk/toolkit/Makefile.am                |  3 ---
 src/fwk/toolkit/goocanvas_proxy_header.hpp | 38 ------------------------------
 2 files changed, 41 deletions(-)
---
diff --git a/src/fwk/toolkit/Makefile.am b/src/fwk/toolkit/Makefile.am
index 9a072697..3742756a 100644
--- a/src/fwk/toolkit/Makefile.am
+++ b/src/fwk/toolkit/Makefile.am
@@ -11,9 +11,6 @@ AM_CPPFLAGS = $(niepce_cppflags)
 
 noinst_LIBRARIES = libniepceframework.a
 
-noinst_HEADERS =   \
-         goocanvas_proxy_header.hpp
-
 TESTS = testconfigdatabinder
 
 check_PROGRAMS = testconfigdatabinder