[gimp] Fix make check by replacing metadata-tags.h with metadata.c as spotted by grem

[Alexandre Prokoudine <aprokoudine src gnome org>]

commit d1bb192d7d3f9c428743bea962b6f447237901d1
Author: Alexandre Prokoudine <alexandre prokoudine gmail com>
Date:   Tue Nov 12 23:36:20 2019 +0300

    Fix make check by replacing metadata-tags.h with metadata.c as spotted by grem

 po-plug-ins/POTFILES.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/po-plug-ins/POTFILES.in b/po-plug-ins/POTFILES.in
index 1b60651482..6e110c46b1 100644
--- a/po-plug-ins/POTFILES.in
+++ b/po-plug-ins/POTFILES.in
@@ -205,7 +205,7 @@ plug-ins/map-object/map-object-apply.c
 plug-ins/map-object/map-object-main.c
 plug-ins/map-object/map-object-ui.c
 plug-ins/metadata/metadata-editor.c
-plug-ins/metadata/metadata-tags.h
+plug-ins/metadata/metadata-tags.c
 plug-ins/metadata/metadata-viewer.c
 plug-ins/pagecurl/pagecurl.c
 plug-ins/print/print-draw-page.c