[gnumeric] Use go_nan instead of infinite for strings that can't be evaluated to numbers in graphs.

[Jean Bréfort <jbrefort src gnome org>]

commit 095d85bd19adeecfd3cd2e43cbcd16141d3d1449
Author: Jean Brefort <jean brefort normalesup org>
Date:   Wed Feb 11 18:29:19 2015 +0100

    Use go_nan instead of infinite for strings that can't be evaluated to numbers in graphs.

 ChangeLog   |    5 +++++
 src/graph.c |    2 +-
 2 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index cfd550b..71c1757 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2015-02-11  Jean Brefort  <jean brefort normalesup org>
+
+       * src/graph.c (cb_assign_val): use go_nan instead of infinite for strings
+       that can't be convered to valid numbers.
+
 2015-02-10  Morten Welinder  <terra gnome org>
 
        * src/gnm-so-line.c (gnm_so_line_draw_cairo): Simplify.
diff --git a/src/graph.c b/src/graph.c
index 9d7d743..ff17043 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -648,7 +648,7 @@ cb_assign_val (GnmCellIter const *iter, struct assign_closure *dat)
                v = format_match_number (value_peek_string (v), NULL,
                                         dat->date_conv);
                if (v == NULL) {
-                       dat->vals[dat->i++] = gnm_pinf;
+                       dat->vals[dat->i++] = go_nan;
                        return NULL;
                }
                res = value_get_as_float (v);