[evolution-data-server] Re-apply missed change for bug 781543 after the offline-cache code merge

[Milan Crha <mcrha src gnome org>]

commit 5eb8d6660c5890c6a93052e164cd368a665c7d8a
Author: Milan Crha <mcrha redhat com>
Date:   Thu May 18 18:13:41 2017 +0200

    Re-apply missed change for bug 781543 after the offline-cache code merge

 .../backends/gtasks/e-cal-backend-gtasks.c         |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/calendar/backends/gtasks/e-cal-backend-gtasks.c 
b/src/calendar/backends/gtasks/e-cal-backend-gtasks.c
index fd2e964..8594072 100644
--- a/src/calendar/backends/gtasks/e-cal-backend-gtasks.c
+++ b/src/calendar/backends/gtasks/e-cal-backend-gtasks.c
@@ -360,7 +360,10 @@ ecb_gtasks_prepare_tasklist (ECalBackendGTasks *cbgtasks,
        }
 
        g_clear_object (&cbgtasks->priv->tasklist);
-       cbgtasks->priv->tasklist = gdata_tasks_tasklist_new (id);
+       if (g_str_has_prefix (id, "gtasks::"))
+               cbgtasks->priv->tasklist = gdata_tasks_tasklist_new (id + 8);
+       else
+               cbgtasks->priv->tasklist = gdata_tasks_tasklist_new (id);
 
        g_free (id);