Update README

corrected path value for site.pp
Merge pull request #15 from beefsalad/master

simple typo correction
Added ability to suppress invalid key warnings on non-openbsd systems
Added tweak to make the unless usage work with suppressed values
variable usage puppet 3.2 ready
Merge pull request #18 from robertpearce/upstream-master

Added ability to suppress invalid key warnings on non-openbsd systems
Merge remote-tracking branch 'github/master'