Upgrade RSpec from 2.14.0 -> 3.1.0

Use the latest available version. This required some changes to avoid
failures, since `true`/`false` no longer respond to `true?`/`false?`.

We also explicitly pass `example` to `method_from_description` since
RSpec no longer allows you to access `example` via `self` in context.

Change-Id: I886f0f514812f760257bd84a759c8d598ec5d034
Reviewed-on: http://gerrit.causes.com/42636
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>
Tested-by: Shane da Silva <shane.dasilva@brigade.com>
Fix RSpec deprecation warnings

The upgrade to RSpec 3 requires that we explicitly enable the `should`
syntax.

Change-Id: I02d8ef2f941324e2aa14b90961ab133b1fb25275
Reviewed-on: http://gerrit.causes.com/42637
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>
Tested-by: Shane da Silva <shane.dasilva@brigade.com>