(PUP-2812) Update FFI License to BSD

 - Update FFI License information provided from LGPLv3 to BSD.
(maint) remove sys-admin license

 - As of Puppet 3.7.0 we will no longer be using this library, so it's best to
   remove the license.
Merge pull request #67 from ferventcoder/ticket/master/PUP-2812-update-ffi-license

(PUP-2812) Update License.rtf