Log Message:
Update ruby-rspec-core to 3.4.4.

### Development
[Full Changelog](http://github.com/rspec/rspec-core/compare/v3.4.4...3-4-maintenance)

### 3.4.4 / 2016-03-09
[Full Changelog](http://github.com/rspec/rspec-core/compare/v3.4.3...3.4.4)

Bug Fixes:

* Fix `RSpec::Core::RakeTask` so that it works with Rake 11.
  (Travis Grathwell, #2197)