Add ssh_command option '--[no-]host-key-verify' when not paranoid.

Very much "inspired" by chefs ssh-command
Adding tests for ssh option --no-host-key-verify
paranoid comment
--no-key-host-verify option also for ssh_args (used by rsync).
ssh_args test
--host-key-verify compare for false instead of nil
Merge pull request #274 from teyrow/add_ssh_option_host_key_verify

Add ssh option --[no-]host-key-verify
Add --no-sync option to skip syncing and only run Chef
Use config_value() to get option state
Add test for --no-sync option
Merge pull request #284 from makern/no-sync-option

Add --no-sync option to skip syncing and only run Chef
Add missing stubs for Librarian and Berkshelf tests
Lock down Berkshelf to <3.0