[gmime] g_mime_text_part_get_text: check if charset filter is available

[Jeffrey Stedfast <fejj src gnome org>]

commit 834c069bd61c43d0a6a09f5b57dd8bd11c098b3e
Author: Jeffrey Stedfast <jestedfa microsoft com>
Date:   Mon Apr 30 10:36:54 2018 -0400

    g_mime_text_part_get_text: check if charset filter is available
    
    Patch by Dirk-Jan C. Binnema

 gmime/gmime-text-part.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gmime/gmime-text-part.c b/gmime/gmime-text-part.c
index d23b0be..af25614 100644
--- a/gmime/gmime-text-part.c
+++ b/gmime/gmime-text-part.c
@@ -277,8 +277,8 @@ g_mime_text_part_get_text (GMimeTextPart *mime_part)
        content_type = g_mime_object_get_content_type ((GMimeObject *) mime_part);
        stream = g_mime_stream_mem_new ();
        
-       if ((charset = g_mime_content_type_get_parameter (content_type, "charset")) != NULL) {
-               filter = g_mime_filter_charset_new (charset, "utf-8");
+       if ((charset = g_mime_content_type_get_parameter (content_type, "charset")) != NULL &&
+           (filter = g_mime_filter_charset_new (charset, "utf-8")) != NULL) {
                filtered = g_mime_stream_filter_new (stream);
                g_mime_stream_filter_add ((GMimeStreamFilter *) filtered, filter);
                g_object_unref (filter);