Fixed a potential double free on error in qtl/shoutcast demuxers.

(cherry picked from commit d9f4825a3fa8b2193a14d41d6f01db1eaa6f3f7a)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

modules/demux/playlist/qtl.c

@@ -148,6 +148,7 @@ static int Demux( demux_t *p_demux )
         msg_Err( p_demux, "invalid root node %i, %s",
                  xml_ReaderNodeType( p_xml_reader ), psz_eltname );
         free( psz_eltname );
+        psz_eltname = NULL;
 
         /* second line has <?quicktime tag ... so we try to skip it */
         msg_Dbg( p_demux, "trying to read one more node" );

modules/demux/playlist/shoutcast.c

@@ -188,7 +188,6 @@ static int DemuxGenre( demux_t *p_demux, xml_reader_t *p_xml_reader,
                         {
                             free( psz_attrname );
                             free( psz_attrvalue );
-                            free( psz_eltname );
                             break;
                         }