[evolution-ews] Fix: 'server_ver' may be used uninitialized in this function [-Wmaybe-uninitialized]

[Fabiano Fidêncio <ffidencio src gnome org>]

commit d3d8982cee10288876cbf9b4173d37d254df0c53
Author: Fabiano Fidêncio <fidencio redhat com>
Date:   Thu May 16 11:27:07 2013 +0200

    Fix: 'server_ver' may be used uninitialized in this function [-Wmaybe-uninitialized]
    
    functionPlease enter the commit message for your changes. Lines starting

 src/server/e-ews-message.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/server/e-ews-message.c b/src/server/e-ews-message.c
index 2bab6d0..5803bfa 100644
--- a/src/server/e-ews-message.c
+++ b/src/server/e-ews-message.c
@@ -40,7 +40,7 @@ e_ews_message_new_with_header (const gchar *uri,
                               gboolean force_minimum_version)
 {
        ESoapMessage *msg;
-       const gchar *server_ver;
+       const gchar *server_ver = "Exchange2007";
        EEwsServerVersion version;
 
        msg = e_soap_message_new (