[goffice] Compilation: use NULL, not 0.

[Morten Welinder <mortenw src gnome org>]

commit 525048dfc2cefb4a8c8e30bcffc298268e2c4fac
Author: Morten Welinder <terra gnome org>
Date:   Mon Mar 25 23:24:05 2013 -0400

    Compilation: use NULL, not 0.

 goffice/utils/go-format.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/goffice/utils/go-format.c b/goffice/utils/go-format.c
index 3f132df..5e99f37 100644
--- a/goffice/utils/go-format.c
+++ b/goffice/utils/go-format.c
@@ -6879,7 +6879,7 @@ find_currency (char const *ptr, gsize len, gboolean precedes)
        gboolean quoted;
 
        if (len <= 0)
-               return 0;
+               return NULL;
 
        if (precedes) {
                has_space = ptr[len - 1] == ' ';