Fix JsonFormatter when --profile is attempted

Created by: JonRowe

When the --profile option is passed to the JsonFormatter it attempts to run dump_profile and output profile information. I believe this is an error stemming from it's creation as a copy+paste from the BaseTextFormatter and has never worked. (see commits 1(https://github.com/rspec/rspec-core/commit/972591b7b874361686882bdc59b97222c45da8ac) 2(https://github.com/rspec/rspec-core/commit/dcfaa67b6886869e6fcb2878ca5e5a1c6e825806) )

In RSpec 3, thanks to #1039, this will work, but for 2-14 we should just kill the bug.