update php53-mcrypt package's md5
update php53-mcrypt package's md5

Just updating the hash to avoid this error:

==> Downloading http://www.php.net/get/php-5.3.16.tar.bz2/from/this/mirror
######################################################################## 100,0%
Error: MD5 mismatch
Expected: 370be99c5cdc2e756c82c44d774933c8
Actual: 99cfd78531643027f60c900e792d21be
Archive: /Library/Caches/Homebrew/php53-mcrypt-5.3.16

TomK/homebrew-php,ablyler/homebrew-php,philcook/homebrew-php,mkalkbrenner/homebrew-php,dguyon/homebrew-php