Revert "Merge pull request #754 from ReactiveCocoa/short-switchToLatest"

This reverts commit 09e3c317c768daeae408a8ef767d41d5ff033858, reversing
changes made to f4ad5be8ff30742d89c77c8cf4778e8de7851d2e.

@kastiglione This introduced a deadlock in the NSControlRACCommandSupportSpec. Still investigating why. :\