Revert "since we're managing .ssh we need to gitignore common files"

This reverts commit 94c3f9773beb09590f1099d14772a2d1a60aef4a.
Revert "point SSH_AUTH_SOCK to a common location on login for use in tmux/wemux http://blog.codersbase.com/2012/03/tmux-ssh-agent.html"

This reverts commit cadf3e5d1a8a36d32f6813d6c6e57ac6d0937e9e.