remove deprecation warning for fixtures

Author: JonRowe

lib/rspec/rails/fixture_support.rb

@@ -22,7 +22,11 @@ module FixtureSupport
           # /TODO
 
           self.fixture_path = RSpec.configuration.fixture_path
-          self.use_transactional_fixtures = RSpec.configuration.use_transactional_fixtures
+          if Rails::VERSION::STRING > '5'
+            self.use_transactional_tests = RSpec.configuration.use_transactional_fixtures
+          else
+            self.use_transactional_fixtures = RSpec.configuration.use_transactional_fixtures
+          end
           self.use_instantiated_fixtures  = RSpec.configuration.use_instantiated_fixtures
           fixtures RSpec.configuration.global_fixtures if RSpec.configuration.global_fixtures
         end