[evolution-ews/wip/camel-more-gobject] Seal CamelDataWrapper properties

[Milan Crha <mcrha src gnome org>]

commit a7d2195c385c1fe36865684d321d97606fa5f9a8
Author: Milan Crha <mcrha redhat com>
Date:   Wed Nov 2 19:39:41 2016 +0100

    Seal CamelDataWrapper properties

 src/calendar/e-cal-backend-ews.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/calendar/e-cal-backend-ews.c b/src/calendar/e-cal-backend-ews.c
index db51e0b..23618a8 100644
--- a/src/calendar/e-cal-backend-ews.c
+++ b/src/calendar/e-cal-backend-ews.c
@@ -2697,6 +2697,7 @@ ewscal_send_cancellation_email (ECalBackend *backend,
                                 const gchar *calobj)
 {
        CamelMimeMessage *message;
+       CamelContentType *mime_type;
        GError *error = NULL;
        CamelMultipart *multi;
        CamelMimePart *text_part, *vcal_part;
@@ -2726,8 +2727,9 @@ ewscal_send_cancellation_email (ECalBackend *backend,
        camel_mime_part_set_content (text_part, body, strlen (body), "text/plain");
 
        vcal_part = camel_mime_part_new ();
-       camel_content_type_set_param (CAMEL_DATA_WRAPPER (vcal_part)->mime_type, "charset", "utf-8");
-       camel_content_type_set_param (CAMEL_DATA_WRAPPER (vcal_part)->mime_type, "method", "CANCEL");
+       mime_type = camel_data_wrapper_get_mime_type_field (CAMEL_DATA_WRAPPER (vcal_part));
+       camel_content_type_set_param (mime_type, "charset", "utf-8");
+       camel_content_type_set_param (mime_type, "method", "CANCEL");
        ical_str = icalcomponent_as_ical_string_r ((icalcomponent *) vcal);
        camel_mime_part_set_content (vcal_part, ical_str, strlen (ical_str), "text/calendar; method=CANCEL");
        free (ical_str);