m3u: factorize.

(cherry picked from commit d69171a2)
Signed-off-by: Rémi Duraffort <ivoire@videolan.org>

modules/demux/playlist/m3u.c

@@ -223,7 +223,7 @@ static int Demux( demux_t *p_demux )
             LocaleFree( psz_parse );
             free( psz_mrl );
 
-            if ( psz_artist && *psz_artist )
+            if ( !EMPTY_STR(psz_artist) )
                 input_item_SetArtist( p_input, psz_artist );
             if( psz_name ) input_item_SetTitle( p_input, psz_name );
 
@@ -242,12 +242,10 @@ static int Demux( demux_t *p_demux )
         {
             /* Cleanup state */
             while( i_options-- ) free( (char*)ppsz_options[i_options] );
-            free( ppsz_options );
-            ppsz_options = NULL; i_options = 0;
-            free( psz_name );
-            psz_name = NULL;
-            free( psz_artist );
-            psz_artist = NULL;
+            FREENULL( ppsz_options );
+            i_options = 0;
+            FREENULL( psz_name );
+            FREENULL( psz_artist );
             i_parsed_duration = 0;
             i_duration = -1;