zip: fix memory leak (cid #1062581)

(cherry picked from commit ed69a40c887aa7550a6e8f1505c9b6388a7d2e5e)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/access/zip/zipstream.c

@@ -598,7 +598,12 @@ static int WriteXSPF( char **pp_buffer, vlc_array_t *p_filenames,
             char *psz_path = strdup( psz_pathtozip );
             char *psz_escapedName;
             escapeToXml( &psz_escapedName, psz_name );
-            if( astrcatf( &psz_path, "%s", psz_escapedName ) < 0 ) return -1;
+            if( astrcatf( &psz_path, "%s", psz_escapedName ) < 0 )
+            {
+                free( psz_escapedName );
+                return -1;
+            }
+            free( psz_escapedName );
 
             /* Track information */
             if( astrcatf( pp_buffer,