[goffice] Fix build.

[Jean Bréfort <jbrefort src gnome org>]

commit aaea50b26ba1c232c696e60f1a2ca7f89ddaf961
Author: Jean Brefort <jean brefort normalesup org>
Date:   Wed Jan 14 13:59:47 2015 +0100

    Fix build.

 plugins/reg_logfit/gog-logfit.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/plugins/reg_logfit/gog-logfit.c b/plugins/reg_logfit/gog-logfit.c
index bfe64c7..445af9a 100644
--- a/plugins/reg_logfit/gog-logfit.c
+++ b/plugins/reg_logfit/gog-logfit.c
@@ -80,9 +80,9 @@ gog_log_fit_curve_update (GogObject *obj)
                g_free (tx_vals);
                g_free (ty_vals);
        } else {
-               model->R2 = go_nan;
+               rc->R2 = go_nan;
                for (i = 0; i < 5; i++)
-                       model->a[i] = go_nan;
+                       rc->a[i] = go_nan;
        }
        g_free (rc->equation);
        rc->equation = NULL;