Fix serial date buglet

[Neil Booth <neil daikokuya demon co uk>]

Gnumeric does not match Excel for the serial date of 28 Feb 1900.
This fixes it.

Neil.

2002-01-13  Neil Booth  <neil daikokuya demon co uk>

        * datetime.c (date_serial_19000228): Should be 59 to match
        Excel for 28 Feb 1900.

Index: datetime.c
===================================================================
RCS file: /cvs/gnome/gnumeric/src/datetime.c,v
retrieving revision 1.15
diff -u -p -r1.15 datetime.c
--- datetime.c  2002/01/10 06:40:20     1.15
+++ datetime.c  2002/01/13 13:35:35
@@ -27,7 +27,7 @@ static int date_origin = 0;
  * The serial number of 19000228.  Excel allocates a serial number for
  * the non-existing date 19000229.
  */
-static const int date_serial_19000228 = 58;
+static const int date_serial_19000228 = 59;
 
 static void
 date_init (void)