[gimp] app: fix warning in xcf_save_prop(): xcf_write_int32() takes guint32*

[Michael Natterer <mitch src gnome org>]

commit a694fdd152c376efe69977c9aff28196a6689116
Author: Michael Natterer <mitch gimp org>
Date:   Tue Nov 15 18:43:51 2016 +0100

    app: fix warning in xcf_save_prop(): xcf_write_int32() takes guint32*

 app/xcf/xcf-save.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/app/xcf/xcf-save.c b/app/xcf/xcf-save.c
index 49c267f..7930b0f 100644
--- a/app/xcf/xcf-save.c
+++ b/app/xcf/xcf-save.c
@@ -763,7 +763,7 @@ xcf_save_prop (XcfInfo    *info,
 
     case PROP_COLOR_TAG:
       {
-        gint32 color_tag;
+        guint32 color_tag;
 
         color_tag = va_arg (args, gint32);
         size = 4;