Update to RSpec 3

Sorry for jumbo PR. This is sorely needed for some upcoming work.

Used transpec to update most of the files. The major exceptions are covering the changes to `pending`. Generally, I use `pending` if an `:if` was supplied, and `skip` if a filter was given or `pending` was not given a block.

\cc @opscode/client-engineers 
If there was already an existing correctly written expectation, shouldn't we leave this alone?  In this case it looks like the method is meant to return true or false, so the `be_false` expectation seems correct.