[gnumeric] Use right size for snprintf

[Morten Welinder <mortenw src gnome org>]

commit 19f55e49593901e8e47efc8109669165fe407b6c
Author: Morten Welinder <terra gnome org>
Date:   Mon Jul 9 19:38:47 2018 -0400

    Use right size for snprintf
    
    Luckily we erred on the safe side.

 src/dialogs/dialog-sheet-compare.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/dialogs/dialog-sheet-compare.c b/src/dialogs/dialog-sheet-compare.c
index 992fb2dad..bafbb2ba6 100644
--- a/src/dialogs/dialog-sheet-compare.c
+++ b/src/dialogs/dialog-sheet-compare.c
@@ -334,9 +334,9 @@ do_color (GnmColor const *gcolor)
 
        GO_COLOR_TO_RGBA (color, &r, &g, &b, &a);
        if (a == 0xff)
-               snprintf (buf, sizeof (coltxt), "#%02X%02X%02X", r, g, b);
+               snprintf (buf, sizeof (buf), "#%02X%02X%02X", r, g, b);
        else
-               snprintf (buf, sizeof (coltxt), "#%02X%02X%02X%02X", r, g, b, a);
+               snprintf (buf, sizeof (buf), "#%02X%02X%02X%02X", r, g, b, a);
 
        for (n = 0; go_color_palette_query (n, &nc); n++) {
                if (nc.color == color) {