Updated spec_helper to conditionally load rspec legacy_formatters only

for older versions of rspec_core.

This was causing crashes upon spec fail.

refer to Origen-SDK/origen_app_generators#15

spec/spec_helper.rb

@@ -20,7 +20,7 @@
 
 require "origen"
 
-require "rspec/legacy_formatters"
+require "rspec/legacy_formatters" if Gem::Version.new(RSpec::Core::Version::STRING) < Gem::Version.new('3.0.0')
 require "#{Origen.top}/spec/format/origen_formatter"
 
 require "byebug"