[evolution] Fix a runtime warning after a change for bug #583773

[Milan Crha <mcrha src gnome org>]

commit 1c53fdf558cf0ad51b54f9a0d1eb06f63931438d
Author: Milan Crha <mcrha redhat com>
Date:   Mon Jan 27 15:49:59 2014 +0100

    Fix a runtime warning after a change for bug #583773
    
    Missed a case when an EMailReader is an EMailBrowser, which is not
    an EMailView, which produced a runtime warning on a console when
    a message was shown in a separate window (like after double-clicking it).

 mail/e-mail-reader.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/mail/e-mail-reader.c b/mail/e-mail-reader.c
index ba73970..0021294 100644
--- a/mail/e-mail-reader.c
+++ b/mail/e-mail-reader.c
@@ -2642,6 +2642,7 @@ mail_reader_load_status_changed_cb (EMailReader *reader,
 
        priv = E_MAIL_READER_GET_PRIVATE (reader);
        if (priv->schedule_mark_seen &&
+           E_IS_MAIL_VIEW (reader) &&
            e_mail_display_get_part_list (display) &&
            e_mail_view_get_preview_visible (E_MAIL_VIEW (reader)))
                schedule_timeout_mark_seen (reader);