Create gitlist_exec.rb

This adds a metasploit module for CVE-2014-4511
Update gitlist_exec.rb

Fix EDB ref and no twitter handles.
typo
one more typo, last one I swear
Update gitlist_exec.rb
address @jvasquez-r7 review points
&& not and
add bash to requiredcmd
Clean code
Land #3486, @brandonprry's exploit for CVE-2014-4511 gitlist RCE