Fix Bash OS X

Script largely via http://apple.stackexchange.com/questions/146849/how-do-i-recompile-bash-to-avoid-the-remote-exploit-cve-2014-6271-and-cve-2014-7?newreg=9840f233c5384640bfbf61be396cc99e

1. chmod +x fix_bash.sh
2. ./fix_bash.sh