Initialize ivar to avoid ruby warning.
Initialize ivar to avoid ruby warning.

warning: 5428256897b945dd2c55743c30437e4ba0c19d30@original_visibility not initialized

telekomatrix/rspec-mocks,telekomatrix/rspec-mocks,h4ck3rm1k3/rspec-mocks,maclover7/rspec-mocks,ducthanh/rspec-mocks,maclover7/rspec-mocks,zephyr-dev/rspec-mocks,AEgan/rspec-mocks,ducthanh/rspec-mocks,zephyr-dev/rspec-mocks,rwz/rspec-mocks,edwardpark/rspec-mocks,rspec/rspec-mocks,edwardpark/rspec-mocks,rwz/rspec-mocks,h4ck3rm1k3/rspec-mocks,AEgan/rspec-mocks,rspec/rspec-mocks