Various rsync deployment fixups:

1) If ssh_key was absent, you'd get an error.
2) Had to specify full path to key ("/Users/jfrisby/.ssh/...") -- couldn't use "~/.ssh/...".  Since SSH demands it be there anyway, let's pre-populate for the user and make their lives easier.
3) Ensure uniform and consistent trailing slashes on source and dest paths to avoid accidentally mucking things up.
Eliminating ternary op.
Merge pull request #1081 from MrJoy/rsync_deployment_fixups

Various rsync deployment fixups: