[balsa] Fix format string error

[Peter Bloomfield <peterb src gnome org>]

commit 270de344b2643365d427891b682b6fbcde037464
Author: Albrecht Dreß <albrecht dress arcor de>
Date:   Mon Jun 10 13:36:49 2019 -0400

    Fix format string error
    
    * src/sendmsg-window.c (sw_insert_sig_activated): fix a “format
      not a string literal and no format arguments” error (using
      gcc w/ -Werror=format-security).

 ChangeLog            | 8 ++++++++
 src/sendmsg-window.c | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/ChangeLog b/ChangeLog
index fefdc7024..0b98e8d7a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2019-06-10  Albrecht Dreß  <albrecht dress arcor de>
+
+       Fix format string error
+
+       * src/sendmsg-window.c (sw_insert_sig_activated): fix a “format
+         not a string literal and no format arguments” error (using
+           gcc w/ -Werror=format-security).
+
 2019-06-10  Albrecht Dreß  <albrecht dress arcor de>
 
        Implement VCalendar stuff using G_*_TYPE()
diff --git a/src/sendmsg-window.c b/src/sendmsg-window.c
index f392deedd..b62ee4e8b 100644
--- a/src/sendmsg-window.c
+++ b/src/sendmsg-window.c
@@ -3777,7 +3777,7 @@ sw_insert_sig_activated(GSimpleAction * action,
     } else if (error != NULL) {
         balsa_information_parented(GTK_WINDOW(bsmsg->window),
                                    LIBBALSA_INFORMATION_ERROR,
-                                   error->message);
+                                   "%s", error->message);
         g_error_free(error);
     }
 }